The Ford Transit is one of the most recognizable vans on the road.
Popular with van-lifers are small business owners alike, the Transit is not immune from nuisance alarms.
If your Transit’s alarm keeps going off, we are here to help.
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Why Does My Ford Transit Alarm Keep Going Off?
A Ford Transit alarm is usually triggered by a faulty door or hood switch. Other common causes include outdated software, a faulty towing hitch sensor, bugs in the cabin triggering the internal sensors, key fob issues and 12V battery issues.
1. Faulty Door Switches
Faulty door switches are another common cause of random alarms on the Transit, similar to the hood switch, these switches monitor the open/closed status of the door – if damaged, faulty or dirty they can send false readings thereby triggering the alarm.
Door switches are a common point of failure as they are subject to wear and tear due to the doors being continually opened/closed/slammed etc.
The door latches and door switches can get dirty too which can cause issues, so the first thing you should do is give all door latches a good clean and spray some WD-40 on the latch and work it in to see if that helps.
Also check the wiring leading from the body into the door for any signs of damage, it should be in a flexible hose on the hinge side of the door.
If you suspect the alarm issues are linked to the door switch, ask your dealer to run a diagnostic test to try and pinpoint the fault.
“I had a similar issue with my van’s alarm, if I unlocked the driver’s door the alarm would go off when I opened the doors. But if I unlocked from the passenger or rear doors the alarm was fine. In the end I found it was the alarm switch (drivers door one) that is attached to the lock barrels inside the doors…” – FordTransit.org
2. Faulty Hood Switch
A faulty hood switch is a common cause of unwanted alarms for Ford vehicles (Transit included).
The switch is typically embedded in the hood latch.
The small electronic device is designed to detect whether the hood is open or shut and is an important part of the car’s alarm system – if it is broken, loose or dirty it can send false readings to the car’s computer thus triggering the alarm.
- Pop the hood and locate the hood switch.
- Check for any obvious damage, rust or loose connections.
- Give the hood switch a clean too (use contact cleaner), as dirt and grime can cause issues.
- You can test the switch with a continuity tester.
If you are well-versed mechanically, you can buy a new hood switch online and replace it yourself. Otherwise, we’d advise visiting your local mechanic.
“This sounds suspiciously like the problem I had, do you ever get the “bonnet (hood) open” warning flash up? Mine was the micro switch in the bonnet catch, just randomly thinking the bonnet was open…” – FordTransit.org
3. Drained 12V Battery
A faulty or weakened car battery causes a variety of problems, including accidentally triggering the Transit alarm.
The best thing to do is take your Transit for a battery health check, these are usually quite inexpensive or sometimes free such as at AutoZone.
Or you can test it yourself with a multimeter (see the guide at the end of this article).
A healthy 12V battery should be about 12.6 to 12.8 volts while a weakened battery reads below 12 volts.
4. Loose or Bad 12V Battery Connections
Loose or bad 12V battery connections can cause a number of problems, including triggering the alarm of your Transit.
A bad connection can be caused by dirt or gunk buildup.
The terminals may have come loose from driving and vibrations etc.
Make sure the engine is off before doing any work on the battery.
- Inspect the battery and look for any signs of damage, dirt build-up, rust, or corrosion.
- Disconnect the battery and loosen the nuts on the clamps using a wrench.
- Remove the negative clamp, marked with a “-” first.
- Clean the terminals with a toothbrush dipped in a mix of baking soda and water, rinse with distilled water and dry with a cloth.
Reconnect the battery, ensuring tight connections.
“It may be as simple as needing to power cycle the system (disconnect the battery for a few minutes) and relax whatever electron log jam you have in whatever circuit.” – FordTransitUSAForum.com
5. Key Fob Low Battery
A common cause of mysterious alarms on the Transit is a low key fob battery. Similarly, if the fob is dirty or dusty this can also cause alarm issues.
Give the inside of your fob a clean and replace the battery to eliminate this possible cause. It’s worth spending a bit extra for a good brand of battery.
- To open your key fob, stick your prying tool into the slit or gap between the two halves of the outer casing and gently apply upward pressure to pop open the device.
- Remove the battery.
- Give the key fob a good clean to remove any dirt or fluff – a cotton swab and some rubbing alcohol should do the trick.
- Check for damage, rust or loose connection (you may need a new key fob depending on what you find).
- Be sure to insert the new battery facing the right way up.
- Assemble the outer casing of your key fob by clamping them back together.
6. Faulty Key Fob
Another reported cause of nuisance alarms on the Transit is a faulty key fob – it may be damaged or just need to be re-programmed.
If you have 2 remotes, try taking the battery out of one and use the other for a while.
If the alarm problems persist, and you have tried cleaning the inside of the fob(s) and changing the battery, the best thing to do is speak with your dealer.
7. Internal Motion Sensors
A common cause of the Transit alarm going off is linked to the interior motion sensors.
Sometimes insects and bugs might get trapped in the cabin or even leaves being blown in, which can be picked up by these sensors thereby triggering the alarm.
You can try disabling the interior sensors by selecting ‘Reduced Guard’ and see if that stops the problem.
You can also try spraying some bug spray in the cabin too.
What Does The Manual Say?
You can select full or reduced guard using the information display.
Full guard – The interior sensors are on when you arm the alarm.
Reduced – The interior sensors are off when you arm the alarm. You can set the alarm to reduced guard for the current ignition cycle only. The alarm will reset to full guard the next time you switch the ignition on.
Ask on exit – You can set the information display to ask you each time which level of guard you wish to set.
Note: Selecting reduced guard does not set the alarm permanently to reduced guard. It sets it to reduced guard only for the current ignition cycle. If you regularly set the alarm to reduced guard, select the option to ask when you exit
Your vehicle may have one of the following alarm systems:
- Category one alarm with interior sensors and battery back-up sounder.
- Perimeter alarm.
Perimeter Alarm: The perimeter alarm is a deterrent against unauthorized access to your vehicle through the doors and the hood.
Interior Sensors (If Equipped): The sensors act as a deterrent against unauthorized intrusion by sensing any movement within your vehicle.
If the interior sensors detect movement within your vehicle it will trigger the alarm.
Note: Do not arm the alarm with full guard if passengers, animals or other moving objects are inside your vehicle, as this could trigger the alarm.
8. Outdated Software
If you are using outdated software on your Transit, you may encounter random errors and glitches, including the car’s alarm going off.
The solution for this is simple: always update your vehicle’s software to prevent any bugs, glitches, or errors.
The best person to speak to will be your dealer.
“A software update to the body control module should cure this [alarm going off]. You need to take it to a dealer, obviously it’s under warranty anyway.” – FordTransit.org
9. Water Leakage
Water leaking into the door latches and sensors can occur thus shorting out electrical circuits and causing issues with the alarm.
A quick fix is to use a hairdryer to dry out any wet parts although long term you will need to fix the leak.
10. Rust and Corrosion on Door and Hood Latches
Rust and corrosion can also damage the latches and switches and they can send false signals to the alarm computer.
If your car is frequently exposed to moisture or other external elements, then you should routinely inspect critical areas of your vehicle for any sign of rust or corrosion.
11. Damaged Wiring
Damaged electrical wiring can cause a wide range of problems, it can often be tricky to pinpoint too and you may need to have an auto electrician run some diagnostic tests.
In some cases a rodent may have chewed through the wiring.
12. Incorrectly Installed Aftermarket Alarm
An incorrectly installed or faulty aftermarket alarm system is a common cause of nuisance alarms.
Aftermarket alarms are typically far more complex than any factory-installed equipment which makes them more prone to issues.
They may also have been installed by incompetent individuals.
If you are experiencing issues with an aftermarket alarm, the best thing to do is speak with a reputable auto electrician.
“Is the system aftermarket? It sounds like it. Some have a motion sensor option using sonar. I had one on my van and had the same issue with it sensing cats on the hood or even somebody getting too close to the driver window…” – FordTransitUSAForum.com
13. Wet Control Module
If you have a tow package (add-on) installed on your Transit, then the control module could be triggering the alarm system.
“The OEM tow pack has an unhitch alarm sensor and the control module is prone to getting wet. You can deactivate internal sensors on switch-off to try and eliminate some of the system…” – FordTransit.org
14. Animals Climbing On The Vehicle
If your alarm has been set off in the middle of the night, it may have been by an animal climbing on the car.
States such as Illinois, Indiana, Iowa, Texas, Wisconsin, and Carolina have large wild raccoon populations.
Have a look for footprints on the hood and the roof.
If you have a CCTV system, examine the footage. These animals usually appear during the night.
15. Not Closing Doors or Hood Properly
Something as simple as not properly closing the doors, hood, or trunk will inevitably trigger the alarm.
Make sure to check if you have closed every point of entry of your vehicle to avoid accidentally tripping your Transit’s alarm.
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.
Disconnect the Battery
Sometimes mysterious alarm problems can disappear with a simple reboot, there are no guarantees here but it’s worth a try.
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 instrument panel?
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 for no money as they plan to make money for the repair of your vehicle.
If your unit is still under warranty then they should fix and resolve the issue for free.
How to Test the 12V Battery
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.