How to silence it right now, what is most likely triggering it, and how to stop it recurring. Owner reports filed with NHTSA point at one cause more than any other — and it is not the one most articles lead with.
ModerateSafe to drive$122–$486 diagnosis through battery replacement typical repair
Quick answer
If it is sounding right now, skip to the section below on silencing it — the short version is to unlock the driver's door with the physical key, then check the owner's manual, and treat disconnecting the battery as a last resort. If you are trying to work out why, start with the hood. Owner complaints filed with NHTSA point at the hood latch switch more consistently than any other single cause, and in one documented case a dealer scan found "security codes relating to hood switch" in the vehicle's security history. After that: a weak battery, a door or trunk latch switch, the key fob, or a control module. We have no reliable published cost for "fixing a car alarm" and we are not going to invent one, but we can give you sourced figures for the individual parts most often involved.
Diagnostic summary
Problem
Car Alarm Keeps Going Off
Severity
ModerateGet it looked at soon
Can you drive?
Safe to drive
A false-triggering alarm does not by itself make a car unsafe to drive. The two things that make it more than a nuisance are that an alarm sounding for hours will flatten the battery — owners have reported exactly that sequence to NHTSA — and that on some vehicles the same underlying control module fault that trips the alarm has produced more serious symptoms. Treat it as urgent for your neighbours and as a diagnostic clue for your car.
Typical repair
$122–$486 diagnosis through battery replacement
Common causes
Hood latch switch or sensor, Weak battery or a poor battery connection, Door or trunk latch switch
Symptoms you might notice
The alarm goes off while the car is parked and locked
Nobody touched it and no door was opened. This is the pattern that points hardest at a latch switch telling the car a door or the hood has just been opened when it has not.
It goes off repeatedly overnight
One of the most commonly searched versions of this problem, and one of the most socially urgent. An owner reported to NHTSA that on their 2016 Civic "the car alarm would go off randomly throughout the night" — the dealership replaced the battery first, which did not solve it, and then found hood switch codes in the security history.
It will not switch off once triggered
An owner reported to NHTSA that on a 2017 Odyssey the alarm activated while parked and "failed to deactivate. The alarm went off for several hours before stopping." The battery went flat days later. This is the case where the alarm becomes the cause of your next problem rather than just an annoyance.
The key fob stops locking or unlocking the car
When alarm trouble arrives alongside the fob failing, that combination points away from a latch switch and towards the module that handles both. An owner reported to NHTSA that on a 2018 CR-V, the first indication of a body control module failure was "my alarm going off and me being unable to enter my vehicle with my key fob."
The battery is flat after an alarm episode
An alarm running for hours draws significant current. This is worth flagging because most advice lists a low battery as a cause of false alarms — it can equally be the consequence, which changes what you should investigate.
A door-ajar indicator showing on the dash when everything is closed
A useful confirming clue. If the dashboard thinks a door is open, so does the alarm system, and you have narrowed the fault to that latch switch.
It goes off in wind, heavy rain, or when a large vehicle passes
The RAC lists strong winds, heavy rain and vibrations from passing vehicles among the triggers, and also notes that open windows or gaps can let insects in to set off interior sensors. This pattern is more typical of aftermarket alarms with shock or motion sensors than of factory systems.
What causes it
1
Hood latch switch or sensor
Very common
This is the cause with the strongest evidence behind it, and it is not the one most articles lead with. We searched NHTSA's complaint database — a US government record of owner-reported failures — for complaints mentioning both an alarm and a hood latch across 36 Honda model years, and the pattern is consistent. One owner of a 2017 Pilot reported: "Alarm randomly goes off when parked and locked without doors being open. Unplugged hood latch sensor and it stopped." A 2016 Civic owner reported that after a battery replacement failed to fix it, the dealership "did a diagnostic check of electronic system and found security codes relating to hood switch in the security history." INFINITI's own parts documentation explains why: the hood latch sensor sits in the engine bay and "is susceptible to dirt and debris." One important caveat from that same Civic complaint: the owner was told by someone with the identical problem that replacing the hood latch assembly was unsuccessful. The evidence points here, but it is not a guaranteed fix.
How to spot it
The alarm triggers with all doors shut and no one near the car, often overnight. Opening and firmly re-closing the hood sometimes stops it for a while.
The fix
Inspect and clean the latch and its switch. Have a dealer read the security system's trigger history before replacing parts.
$196–$237 hood latch replacement, RepairPal — see costs•Moderate DIY
2
Weak battery or a poor battery connection
Very common
INFINITI states plainly that "a dying battery or a poor battery connection can both trigger your INFINITI's car alarm," and the RAC lists a weak battery, a faulty alternator or loose connections among the causes. Low voltage makes control modules behave unpredictably, and an alarm system interpreting a voltage dip as a tamper event is a well-recognised failure mode. But watch the direction of causation — see the section below on the trap this creates.
How to spot it
Slow crank, dim lights, or alarm episodes that cluster in cold weather when battery capacity drops.
The fix
Clean the terminals and clamps with a wire brush to remove corrosion, and test the battery properly rather than replacing on suspicion.
The same failure as the hood latch, in a different place. INFINITI notes that "dirt, debris, and water can all affect the door lock sensor, interrupting the sensor's ability to tell your vehicle the door is closed." A sensor that intermittently reports a door as open will intermittently trip the alarm.
How to spot it
A door-ajar indicator on the dashboard when everything is closed, or an interior light that stays on. Check the dash before you check anything else — it is free.
The fix
Clean the latch mechanism and its switch. Water ingress into a door is a common underlying cause.
No reliable published range•Moderate DIY
4
Key fob fault or radio interference
Common
INFINITI lists damaged buttons or faulty signals from the fob among the causes. The RAC adds a low fob battery, a malfunctioning remote, and "key fob interference" from "electronics like smartphones or other key fobs." A fob in a pocket pressing its own panic button is a genuinely common and slightly embarrassing explanation.
How to spot it
Episodes that happen when you are near the car rather than when it is alone, or that stop when you use the spare fob.
The fix
Replace the fob battery and test with the second fob. If the second fob behaves differently, you have found it.
No reliable published range•DIY friendly
5
Body control module or keyless access unit failure
Occasional
Barely covered anywhere else, and well documented in NHTSA's complaint database. Owners have reported: on a 2018 CR-V, "my body control module (BCM) seems to have failed... my first indication was my alarm going off and me being unable to enter my vehicle with my key fob"; on a 2018 Civic, a BCM malfunction where "I was first alerted to this from a car alarm going off," after which the owner was locked out entirely with both fob and physical key and found the car had entered accessory mode unattended; on another 2018 Civic, a faulty BCM where the "alarm horn went on when car is off"; and on a 2016 Pilot, a defective keyless access unit causing the anti-theft alarm horn to sound alongside battery drain and flashing lights. These are unverified consumer reports rather than confirmed defects, but the pattern is consistent enough to be worth knowing.
How to spot it
The alarm problem arrives together with other electrical oddities — fob failures, lockouts, lights behaving strangely. That combination is the signature.
The fix
Requires dealer-level diagnosis. There is no reliable published cost for module replacement and we are not going to estimate one.
No reliable published range•Shop recommended
6
Over-sensitive shock or motion sensors
Occasional
The RAC lists strong winds, heavy rain and vibrations from passing vehicles as triggers, and notes that open windows or gaps allow insects in to set off interior sensors. This is much more typical of aftermarket alarm systems, which often include shock and motion sensing that factory systems do not. Many aftermarket units have an adjustable sensitivity setting — but the adjustment procedure is specific to the unit, so consult that manufacturer's own documentation rather than a generic instruction.
How to spot it
Episodes correlated with weather or with traffic passing close by, on a car with an aftermarket alarm fitted.
The fix
Consult the alarm manufacturer's documentation for the sensitivity adjustment. Close windows fully.
No reliable published range•Moderate DIY
7
Faulty wiring or poor aftermarket installation
Occasional
The RAC names "a faulty sensor or wiring" and Confused.com lists poor alarm installation. An aftermarket alarm spliced into the factory harness by someone in a hurry is a recurring source of intermittent, weather-dependent faults that nobody can reproduce on demand.
How to spot it
The problem started after an alarm, stereo or tracker was fitted, or after any work involving the wiring.
The fix
Have the installation inspected. If it was recent, go back to whoever did it first.
No reliable published range•Shop recommended
How to diagnose it
1
Check the hood is fully latched, then look at the latch itself
Start here because this is where the evidence points. INFINITI's guidance is to ensure the hood is firmly latched, and notes the hood latch sensor "is susceptible to dirt and debris" because of where it lives. Open the hood, look at the latch mechanism and its switch, and clean out accumulated grime and leaf litter. Close it firmly rather than dropping it.
Tools: Flashlight, Cloth or brush
Result: Either the false triggers stop, or you have ruled out the most commonly reported cause.
2
Look for a door-ajar indicator on the dashboard
Free and instant. If the dash thinks a door, the tailgate or the trunk is open when it is not, that latch switch is your fault and you have skipped several steps. INFINITI notes that dirt, debris and water all affect these sensors' ability to report that a door is closed.
Result: A specific latch identified, or that possibility eliminated.
3
Clean the battery terminals and test the voltage
INFINITI recommends cleaning the battery terminals and cable clamps with a wire brush to remove corrosion. Then measure the voltage. A note on thresholds: we have seen a "replace the battery if it reads below 12.6 volts" rule published on this topic and we are not repeating it, because it conflates state of charge with battery health. Optima's framing is the one we would use — keeping voltage above 12.4 volts matters for long-term battery life, below which sulfation begins to diminish capacity and performance.
Tools: Wire brush, Digital multimeter
Result: A clean connection and a real voltage reading rather than a guess.
4
Change the fob battery and test the spare
The RAC lists a low fob battery or a malfunctioning remote among the causes. Swap the battery in your main fob and then deliberately use the spare for a few days. If the behaviour changes, the fob was involved. INFINITI also suggests simply locking and unlocking with the fob to test that the mechanism is responding as it should.
Tools: Replacement coin cell, Small screwdriver
Result: The fob confirmed or eliminated as the trigger.
5
Ask a dealer to read the security system's trigger history
This is the highest-value step on this page and it is essentially unpublished anywhere else. On at least some vehicles, the security system logs which sensor triggered the alarm, and a dealer scan tool can read it. The evidence is a complaint filed with NHTSA about a 2016 Civic, where the dealership "did a diagnostic check of electronic system and found security codes relating to hood switch in the security history." That is the difference between diagnosing this and guessing at it. We cannot tell you every vehicle stores this — that is not something we can source — but it is worth asking, and it may save you the cost of replacing the wrong part.
Result: A named trigger source rather than a shortlist.
6
Escalate to professional diagnosis
INFINITI recommends having a technician run diagnostics for sensor faults, and going to an authorised service centre for anti-theft system reset or repair. If the alarm problem is arriving alongside fob failures, lockouts or other electrical oddities, that combination points at a control module and is not something to chase with a multimeter.
Result: A diagnosis on the systems an owner cannot reach.
Repair options & cost
Clean the hood, door and trunk latch switches
Free, and it addresses the most commonly reported cause. Dirt and debris on a latch switch is a maintenance issue rather than a failure, and cleaning it is worth doing before anything gets replaced.
No reliable published rangeDIY friendly
Key fob battery replacement
A few dollars and five minutes. Worth doing early simply because it is so cheap to eliminate.
No reliable published rangeDIY friendly
Battery terminal cleaning, or battery replacement
Cleaning costs nothing. Replacement, per RepairPal's national average, runs $449–$486 with $60–$88 of that being labour. Test before replacing — and read the section below on why the battery may be a symptom rather than the cause.
$449–$486 installed, RepairPalModerate DIY
Hood latch replacement
Two sources give different labour figures and we are publishing both. RepairPal's national average for hood latch replacement is $196–$237, of which $79–$116 is labour. CarParts.com puts the labour at "average between $50 and $70." We are not averaging them. Two further caveats from RepairPal's own page: latches include "the alarm switch if so equipped" — meaning the switch is not always part of the latch assembly, so confirm what you are actually buying — and if the release cable also needs replacing, "the procedure is markedly more complicated."
$196–$237 RepairPal; labour disputed, see noteModerate DIY
Professional electrical diagnosis
RepairPal puts electrical system diagnosis at $122–$179. If you have cleaned the latches, changed the fob battery and tested the battery without result, this is the sensible next spend — it is less than the cost of replacing one wrong part.
Anti-theft module, alarm control unit and fob reprogramming
We found no defensible published cost range for any of these and we are not going to estimate. This includes body control module replacement, alarm control unit repair, aftermarket alarm removal and key fob reprogramming. The variation between vehicles is enormous, and a module that requires programming to the vehicle costs very differently from one that does not. Get a quote against a specific diagnosis rather than against a symptom.
No reliable published rangeShop recommended
There is no reliable published cost for "fixing a car alarm that keeps going off," and we are showing you the gap rather than filling it. What we can source are figures for the specific parts most often implicated: electrical system diagnosis at $122–$179, hood latch replacement at $196–$237, and battery replacement at $449–$486, all RepairPal national averages excluding taxes and fees. Note that two sources disagree on hood latch labour — RepairPal says $79–$116, CarParts.com says $50–$70 — and we publish both rather than averaging. For anti-theft module replacement, alarm control unit repair, aftermarket alarm removal and key fob reprogramming we found no defensible range at all. Costs vary by vehicle, location, labour rate and parts.
When to see a mechanic
▸The alarm arrives together with other electrical faults — the fob failing, being locked out, lights behaving oddly. That combination points at a control module and owners have reported serious consequences from those, including being completely locked out of the vehicle.
▸It has already flattened your battery once. The next episode will do it again, and a repeatedly deep-discharged battery does not recover fully.
▸You have cleaned the latches, changed the fob battery and tested the battery, and it is still happening. Pay for the diagnosis rather than the next guess.
▸You want the security system's trigger history read. That needs a dealer scan tool, and it converts guesswork into a diagnosis.
▸The problem started after an alarm, stereo or tracker was installed. Go back to the installer.
▸You are considering disabling the alarm. Read the section on that first — the consequences are larger than most people expect.
How to silence an alarm that is sounding right now
If you are standing next to a car that will not stop, this is the section you need. The steps below are in the order the RAC gives them, and the emphasis on the manual is deliberate — it is the only step that is correct for every vehicle.
1
Unlock the driver's door with the physical key
Use the metal key in the driver's side door lock rather than the remote. The RAC lists this first, and on many vehicles it resets the alarm because the car recognises a legitimate key in the lock.
2
Press unlock on the fob, or start the engine
Near-universal and low risk. Starting the engine with a valid key or fob present tells the security system the person present is authorised.
3
Press the dashboard alarm off button if your vehicle has one
Some vehicles have a dedicated control. The RAC mentions it, though it is far from universal.
4
Check the owner's manual
The RAC lists this and we would emphasise it above the others, because it is the only step guaranteed to be correct for your specific car. Manufacturers document the alarm reset procedure and it varies.
5
Disconnect the battery — last resort only
The RAC frames this explicitly as a last resort and warns it "may wipe your car's onboard computer and/or infotainment system." You may lose radio presets, seat memory and stored settings, and on some vehicles relearning idle or window positions is required afterwards. Do not treat it as a routine step.
The battery trap: cause or consequence?
Almost every article on this topic lists a low battery as a cause of false alarms, and that is genuinely true — INFINITI states that a dying battery or poor connection can trigger the alarm, and the RAC lists a weak battery among the causes. But nothing we found points out that the causation runs both ways, and missing that sends people down the wrong path.
An owner reported to NHTSA that on their 2017 Odyssey, the alarm activated while parked and "failed to deactivate. The alarm went off for several hours before stopping." The battery drained days later and was replaced under warranty. The failure then recurred — and the vehicle "was diagnosed with a defective hood latch." The flat battery was a symptom of the alarm problem, not its cause.
The same pattern shows up in another complaint: a 2016 Civic owner whose alarm went off randomly overnight took it to the dealer, who "checked and replaced" the battery. It did not solve the issue. On the second visit they found hood switch codes in the security history.
The diagnostic step almost nobody knows about
Here is the single most useful thing on this page, and we found it in a US government complaint database rather than in any article about car alarms.
An owner of a 2016 Honda Civic filed a complaint with NHTSA describing exactly the problem you probably have — the alarm going off randomly through the night. After a battery replacement failed to fix it, they went back, and this time: the dealership "did a diagnostic check of electronic system and found security codes relating to hood switch in the security history."
That matters because it means the vehicle recorded which sensor tripped the alarm. Instead of a shortlist of seven possible causes and a sequence of replaced parts, there was an answer stored in the car the whole time.
One further caveat from that same complaint, which we include because leaving it out would overclaim: the owner noted that another person with the identical problem reported that replacing the hood latch assembly was unsuccessful. The trigger history tells you what set the alarm off. It does not guarantee the obvious repair will hold.
What owner reports to NHTSA actually show
Most pages on this topic order the causes by what other pages say. We wanted something better, so we searched NHTSA's complaint database — the US government's record of owner-reported vehicle failures — across 36 Honda model years for complaints mentioning both an alarm and a hood latch, switch or sensor.
Vehicle
What the owner reported
Complaint ID
2016 Honda Civic
Alarm went off randomly overnight. Dealer replaced the battery, which did not solve it. A second visit found security codes relating to the hood switch in the security history.
ODI 11166125
2017 Honda Pilot
"Alarm randomly goes off when parked and locked without doors being open. Unplugged hood latch sensor and it stopped but security system is not armed."
ODI 11721322
2017 Honda Odyssey
Alarm activated while parked and ran for several hours. Battery drained days later. Diagnosed with a defective hood latch; the failure then recurred and was attributed to the alternator.
ODI 11595165
2018 Honda CR-V
Body control module failure; "my first indication was my alarm going off and me being unable to enter my vehicle with my key fob."
ODI 11737331
2018 Honda Civic
BCM malfunction, first noticed via the alarm. Owner locked out entirely with both fob and physical key; vehicle had entered accessory mode unattended.
ODI 11552022
2016 Honda Pilot
Defective keyless access unit; anti-theft alarm horn sounding alongside battery drain, flashing lights and a defective hood latch.
ODI 11589452
Selected owner complaints filed with NHTSA
The signal in this set is the hood latch switch, and it is consistent enough that we have put it first in the causes above rather than leading with the battery as most pages do.
A recall that exists, and what it does not say
There is a verified NHTSA recall in this area — campaign 20V771000 — covering certain 2018–2020 Honda Accord Sedan and Accord Hybrid and 2019–2020 Insight vehicles for a body control module software error causing "intermittent or continuous disruptions in communication between the Body Control Module (BCM) and other components." The remedy is a free BCM software update at a dealer.
How long is a car alarm legally allowed to sound?
Nothing in the ranking results on this topic covers this, which is odd given how many people arrive here because of somebody else's car. The short answer is that this is governed by municipal ordinance, not federal law, so the rule depends entirely on where you are. Here are three documented examples.
City
The limit
Source
New York City
An alarm "shall be capable of and shall terminate its audible response within three minutes of its being activated." The same section restricts activation to direct physical contact with the vehicle, or a remote used from no further than 15 feet away, and separately prohibits audible status indicators — the chirp on locking.
NYC Admin Code §24-238
Philadelphia
"Any sounding of an audible anti-theft alarm from a motor vehicle for more than five (5) continuous minutes shall be deemed a violation." Also prohibits alarms activating without direct physical contact, except when remotely activated by the owner.
Philadelphia Code §12-1123
Los Angeles
Reported by FindLaw as a five-minute automatic-silence requirement in the Municipal Code. We are attributing this to FindLaw rather than stating it as verified, because we have not read the ordinance text ourselves.
FindLaw summary — unverified against the code
Examples of municipal car alarm ordinances
If your own alarm is the one running for hours, note that the NYC and Philadelphia limits are in the range of three to five minutes. An alarm that sounds until the battery dies is not merely antisocial in those jurisdictions.
If it is your neighbour's car, not yours
This is a real audience that the existing content on this topic serves almost exclusively via forum threads. What we can tell you with a source: New York City's 311 service states that "you can report a car, house, or other alarm that goes off too often or for too long." Most cities with a duration ordinance have a corresponding reporting route, usually through a non-emergency municipal line rather than the police.
Should you just disable the alarm?
It is the obvious thought after the third night, and it is worth understanding what you would be trading away. We are going to describe the consequences rather than give you a procedure, and we will say why at the end.
The RAC strongly discourages disabling a vehicle alarm and lists four consequences:
Disconnecting the battery as part of the process "may wipe your car's onboard computer and/or infotainment system."
"It will make your car easier to steal." This is the obvious one, and it is still worth stating plainly.
"If your vehicle doesn't have an alarm, it can impact your insurance." Worth checking your policy wording before rather than after.
You lose the witness effect — an alarm brings attention to an attempted theft, and without it, nobody looks.
There is a concrete illustration of the trade-off in the NHTSA complaints. The 2017 Pilot owner who unplugged the hood latch sensor did stop the false alarms — and reported in the same breath that the "security system is not armed (absence of blinking light)." The fix worked by switching the security system off. That is the deal, stated by someone who made it.
Our position: a false-triggering alarm is a fault with a cause, and the cause is usually a dirty or failing latch switch. That is a repair. Disabling the system is not a repair, it is a permanent downgrade to the car, and it is worth exhausting the diagnosis first — starting with asking a dealer to read the trigger history.
▸Why does my car alarm keep going off for no reason?
There is a reason — it is just not one you can see from where you are standing. The evidence points hardest at the hood latch switch. Owners have reported to NHTSA that unplugging the hood latch sensor stopped the false alarms, and in one case a dealer scan found "security codes relating to hood switch in the security history" after a battery replacement had failed to fix it. INFINITI notes the hood latch sensor "is susceptible to dirt and debris" because of where it sits in the engine bay. After that, in rough order: a weak battery or corroded connection, a door or trunk latch switch, the key fob, or a control module. Start by cleaning the hood latch, then check whether the dashboard shows a door-ajar indicator.
▸How do I stop a car alarm that is going off right now?
Try these in order, following the RAC's sequence. Unlock the driver's door with the physical key rather than the remote — this resets the alarm on many vehicles. Press unlock on the fob, or start the engine with a valid key present. Press the dashboard alarm off button if your car has one. Then check the owner's manual, which is the only step guaranteed to be correct for your specific vehicle. Disconnecting the battery is a genuine last resort: the RAC warns it "may wipe your car's onboard computer and/or infotainment system." We are deliberately not telling you to pull the alarm or horn fuse — that advice circulates widely but traces back to forum posts rather than any authority, and it disables the horn too.
▸Can a bad battery make the alarm go off?
Yes, and also the reverse — which is the part almost nobody mentions. INFINITI states that "a dying battery or a poor battery connection can both trigger your INFINITI's car alarm," and the RAC lists a weak battery among the causes. But an alarm sounding for hours will also flatten a healthy battery. An owner reported to NHTSA that their Odyssey's alarm "went off for several hours before stopping," after which the battery drained and was replaced — and the real fault turned out to be a defective hood latch. If your battery went flat after an alarm episode rather than before it, replacing it will not stop the alarm. Test the battery, but do not assume it is the explanation.
▸How much does it cost to fix a car alarm that keeps going off?
We could not find a defensible published range for "car alarm repair" and we are not going to invent one. What we can source is the cost of the parts most often involved. RepairPal's national averages: electrical system diagnosis $122–$179, hood latch replacement $196–$237, battery replacement $449–$486. Note that two sources disagree on hood latch labour — RepairPal says $79–$116 while CarParts.com says $50–$70 — so we publish both. Also note RepairPal's caveat that latches include "the alarm switch if so equipped," meaning the switch is not always part of the latch. For anti-theft module replacement, alarm control unit repair, aftermarket alarm removal and key fob reprogramming we found no defensible figures at all. Costs vary by vehicle, location, labour rate and parts.
▸Can I call the police about a car alarm that keeps going off?
In many cities the route is a non-emergency municipal line rather than the police. New York City's 311 service states directly that "you can report a car, house, or other alarm that goes off too often or for too long." Whether the alarm is actually in violation depends on your local ordinance, because this is municipal law, not federal. Two documented examples: New York City requires an alarm to terminate its audible response within three minutes of activation, and Philadelphia deems any sounding for more than five continuous minutes a violation. Check your own city's code — there is no national rule, and the limits vary.
▸Should I just disable the alarm?
We would exhaust the diagnosis first, and we are not going to publish a disable procedure. The RAC strongly discourages it and gives four reasons: the battery disconnection involved "may wipe your car's onboard computer and/or infotainment system"; "it will make your car easier to steal"; "if your vehicle doesn't have an alarm, it can impact your insurance"; and you lose the witness effect during an attempted theft. There is a real illustration in the NHTSA complaints — the owner who unplugged the hood latch sensor did stop the false alarms, and noted in the same report that the "security system is not armed." The false alarms went away because the security system went away. A dirty latch switch is a repair; this is a permanent downgrade.
▸Why does it only happen at night or in bad weather?
Temperature and moisture are the usual explanations. Cold reduces battery capacity, so a marginal battery reads lower overnight than it does in the afternoon, and low voltage makes control modules behave unpredictably. Moisture affects latch switches — INFINITI notes that dirt, debris and water all interfere with a door sensor's ability to report that the door is closed. If the pattern correlates with wind or passing traffic rather than with time of day, that points at shock or motion sensors, which the RAC lists as susceptible to strong winds, heavy rain and vibrations from passing vehicles. Those are far more common on aftermarket alarm systems than on factory ones.
▸The alarm goes off and my key fob has stopped working. What does that mean?
That combination is a meaningful signal and it points away from a latch switch. Owners have reported to NHTSA that a body control module failure presented exactly this way: on a 2018 CR-V, "my first indication was my alarm going off and me being unable to enter my vehicle with my key fob"; on a 2018 Civic, a BCM malfunction first noticed via the alarm left the owner locked out with both the fob and the physical key failing, and the car had entered accessory mode unattended. These are unverified owner reports rather than confirmed defects, but the pattern is consistent. Try the spare fob and a fresh fob battery first to eliminate the simple explanation — then get it diagnosed properly rather than replacing latch switches. Car electrical problems covers what a module fault looks like more broadly.