The Explorer is one of the most recognizable SUVs on the roads today.
Despite being a robust vehicle, it’s not uncommon for the alarm to play up.
If you’re Explorer alarm keeps going off, this article is here to help.
Why Does My Ford Explorer Alarm Keep Going Off?
The most common causes of the alarm going off on a Ford Explorer is a faulty hood switch, door sensor issues or problems with the rear hatch latch. Other causes include a dying 12V battery, a faulty body control module, a low key fob battery and wiring issues.
If your Explorer alarm is going off when it shouldn’t then by process of elimination, it shouldn’t be too hard to find the root cause...
1. Hood Switch Problems
Like most vehicles the Explorer utilizes a hood latch sensor which is essentially an electrical switch.
It is designed to trigger an alarm if someone tries to force open the hood, however if it is broken or clogged with dirt this can trigger the alarm.
Dirty Hood Switch
Due to the prominent location of the hood switch, it is very prone to getting dusty, dirty and grimy – the accumulation of which is enough to cause alarm issues. Corrosion and rusting of the hood switch is also very common, which can also trigger the alarm.
Give the switch a thorough clean and make sure it is completely free of dirt and debris.
It’s also a good idea to spray a little WD40 too for some much-needed lubrication.
Faulty Hood Switch
It’s not uncommon for the hood switch to develop a fault or get damaged from the bumps of driving, from slamming the hood or from exposure to weather.
If the switch that monitors whether the hood is open or shut isn’t working then this will impact the alarm.
If you’re mechanically inclined it’s not too difficult to replace these and you can pick a new one up from autozone for just over $100.
If not have your Ford dealer take a look.
Here’s what a couple of Ford owners had to say:
“For those of us that had it previously [alarm going off at random] it was the hood alarm triggering it. There is a “plunger” like sensor under the hood that goes bad.”
“When my alarm kept going off it was the switch under the hood, passenger side, that was loose (guy at the body shop forgot to tighten it back down)”
2. Faulty Door Sensor
A faulty door latch sensor is a common cause of Ford Explorer alarms going off.
Similar to the hood latch sensor, your Explorer alarm monitors the doors to make sure no one is opening them.
It’s a good idea to give all door latches a clean and some lubrication with WD-40.
Here’s what a few Explorer owners had to say:
“I had this issue on my F350.. took me over a year to figure it out. Door sensor was going bad and randomly for a millisecond would trigger and that’s all it took. I’d drive and hear a chime but by the time I looked down, it was gone. Finally I caught it… a quick door ajar alert. Not saying this is your issue but it is a good possibility”
“It seems the door switch replacement was successful. Haven’t had the door ajar light come on, nor has the alarm randomly gone off since replacing the switch on Wednesday.”
“After 2 months of not sleeping because of the alarm going off, as a last ditch effort I went to the dealer and they found that one of the door ajar sensors had shorted. This is why the alarm would go off at night, the dome lights would come on and off while driving, and the doors would unlock and lock because the computer thinks the door has come ajar when nothing at all has happened in reality. The best $260 I’ve ever spent.”
If you suspect the door sensor is faulty and your car is still under warranty we recommend taking it to the dealer and having them replace it for free.
3. Rear Hatch Latch
Similar to the door sensors and hood switch, the rear hatch latch can also be a common culprit when it comes to alarms going off at random.
Here’s what happened to one owner when they took their Explorer to their dealership:
“I was able to convince the dealer to look at it yesterday. They were able to query the computer to see that the alarms were triggered by the rear hatch (which I rarely open, but actually realize now that the alarms stopped after I opened and closed it). They offered to replace the latch, but I declined for now since it isn’t doing it. If it acts up again, replacing the latch will be the next step.”
4. Dying 12V Battery
A dying 12V battery or a battery with low voltage can cause a slew of problems, including activating the alarm of your Explorer. This should really be the first thing you check as it’s a very common cause and it’s easy enough to check and fix.
Most 12V car batteries last about 3-4 years so it might be time for a new one.
It’s always worth cleaning the terminals first though and making sure the connections are tight and free from dirt, gunk and debris.
Tip: Clean the terminals using a toothbrush dipped in baking soda and water mixture
Failing that, the next step is to check the battery, you can do this with a multimeter.
Here’s what one Explorer owner had to say:
“Try another battery for a week and see if it doesn’t straighten out. The battery voltage needs to be well over 12.6 v to hold the relays open.
Also, clean the connections real well, double check the 10 gauge black ground leads to the radiator support. Should be <2 ohms”
How to Test the Battery
- Before testing, remove the surface charge from the battery, this allows for an accurate reading.
- Simply turn on the headlights for 2 minutes then turn off.
- Set the multimeter dial to the ’20 Volts’ setting.
- Make sure the car is turned OFF
The multimeter will have a red probe and a black probe:
- The red probe is for making contact with the positive terminal
- The black probe is for making contact with the negative terminal.
Measure across the battery terminals.
The meter should display a reading, if the battery is fully charged the voltage should be between 12.2 and 12.6 volts.
Anything under 12V and the battery should be charged or replaced.
If you’re not confident doing this, take your truck to any AutoZone who often offers free battery health checks.
5. Faulty Body Control Module
A common reason why a Ford Explorer alarm keeps going off is due to a faulty body control module.
The body control module or ‘body computer’ is the electronic control unit responsible for monitoring and controlling various systems associated with the vehicle’s body such as the alarm, immobilizers, power windows etc.
The body control module can develop corrosion on the pins or connections can become loose.
You can typically pick one up for around $700 and if you’re not mechanically inclined it’s probably best to have someone at Ford fit it for you.
Other common symptoms of a bad BCM include:
- Repeated battery drain
- Starting problems
- Erratic electrical functions e.g. horn, wipers, lights, lights on the dash
- Security and alarm system problems
6. RFI and EMR
RFI is Radio Frequency Interference and EMR is electromagnetic radiation, both of which can cause the alarm to be triggered on your Explorer.
For example, parking underneath overhead power lines will expose your car to high amounts of EMR which can interfere with the electronics on your alarm system.
If you suspect this is the cause, try parking somewhere else out the way.
Here’s what one Ford owner had to say:
“There probably is some sort of RFI being generated around where you park at work which is making your car go insane.”
7. Low Key Fob Battery / Faulty Key Fob
As the key fob also has controls linked with your Explorer alarm system, a faulty, damaged or malfunctioning key fob can send an incorrect signal, which may trigger the alarm. A low key fob battery can cause the alarm on your car to go off at random.
Try using your spare coded key – if the problem goes away then you know you’ll need to replace the battery in your primary key fob.
It’s also advised that you don’t carry big metal objects, electronics or a second coded key on the same keyring as your primary key fob as this can lead to problems also.
It might also be worth giving the inside of your key fob a clean as these can get filled with dirt which could be causing the alarm issue.
In summary, if you suspect your problems might be key fob related you can try the following:
- Check and replace key fob batteries
- Clean the key fob
- Reset the key fob
- Reprogram the key fob
Here’s one owner’s advice:
“I’d say the first thing to try would be to spend the $6 and get a couple of new batteries for the FOB and if it still does it then you have a bigger problem. I always try to weed out the simple problems 1st. If $6 fixes the problem then you won’t have to spend any money taking the car to the dealer to diagnose the problem.”
8. Damaged Wiring
Although this is quite vague, damaged wiring can very easily cause a lot of problems for the alarm system.
Here is what one owner on ExplorerForum.com had to say:
“Had the same problem on my ’02. Turned out to be broken wires in the drivers side door. Once fixed, never came up again. Made neighbors happy.”
Disconnect the Battery
Sometimes mysterious alarm problems can disappear with a simple reboot, there are no guarantees here but it’s worth a shot.
Disconnect the battery for 20 seconds and this resets many of the electronics in the vehicle.
Check For Warning Messages
When the alarm occurs can you see any lights or warning messages on the gauge cluster?
This can give a clue as to what’s causing the alarm e.g. ‘Hood Ajar’.
Take it to a Ford Dealership
If needed, take your Ford to the dealership.
Tell them you are NOT paying for a check on what the problem might be.
Ask them if they will check it for free.
Most dealerships and other places do quick/initial diagnosis (run computer tests to see exactly what is triggering the alarm) for no money as they plan to make money for the repair of your vehicle.
If you’re Ford is still under warranty then they should fix and resolve the issue for free.
Check for Recalls or TSBs:
By entering your car’s VIN number on Ford’s recall page or the NTHSA’s Safety Issues & Recalls page you can determine whether or not there is a TSB or recall for your vehicle and if there is you’ll want to get it addressed.
A recall is issued by a vehicle manufacturer for issues that are safety-related, while a TSB covers components that may be malfunctioning but don’t compromise the safety of the vehicle.