The Grand Cherokee is one of Jeep’s all-time best sellers.
Despite its rugged persona, it’s not uncommon for the alarm to go off at random.
If your Grand Cherokee alarm keeps going off, this article offers the most common reasons why.
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Why Does My Jeep Grand Cherokee Alarm Keep Going Off?
According to owners, the most common reasons why a Jeep Grand Cherokee alarm goes of at random is due to a faulty or dirty hood switch (hood latch sensor). Other common causes include bugs triggering the internal sensors, doors and windows not closed properly, software update required, accidental pressing of the panic alarm on the fob, 12V battery issues and key fob issues.
1. Faulty Hood Switch
According to numerous Grand Cherokee owners, a faulty hood switch is a common cause of nuisance alarms. The hood switch is a small electrical switch that monitors whether the hood is open or shut, if the switch is faulty it can send false signals to the car thus triggering the alarm.
If the switch is faulty, replacing it should solve the alarm issues.
If the switch (sensor) is dirty or has a loose connection this can also cause alarm issues, so it’s a good idea to make sure that it is free from debris and is not loose.
Here is what Grand Cherokee owners had to say on the popular forum jeepgarage.org:
“The most exposed door switch is the one in the bonnet [hood] catch… it might have water in it. Try locking the car with the bonnet [hood] switch unplugged, and it that offers no change, bridge it out (ie: join the two wires while still unplugged).
“Thanks a million SNUKE, after going over the sensor in the hood. Haven’t had any problems what-so-ever with the alarm.”
“On the drivers side shock tower is the hood sensor. Just have a look at it to make sure its not came loose or looks funny.”
“Thanks for the help Scott! I checked the sensor you mentioned and it was fine. I then noticed that the remote start was not working. When I got in the car, there was an error message on the gauge cluster that said something like “remote start disabled – hood open”. I then cleaned the sensor – it was located on the passenger side of the hood latch. I think that did it. The remote start now works and even better, no more alarm!”
“This is occurring on a few 2014 WK2’s on the regular board. Some have had the hood latch/switch replaced.”
“My alarm was going off all the time. Read this thread. Fiddled with the sensor. Now have no issues with the alarm. Hasn’t gone off in a week!”
“That worked for me, but when I was in for service they determined it was a bad hood latch and sensor. It was replaced and there have been no more issues. I would take it in and see what they can do for you.”
“Defective hood latch switch. Replaced twice. Cold weather issue.”
2. Interior Sensors Triggered By Bugs
Some nuisance alarms of the Grand Cherokee can be triggered by bugs flying inside the cabin thereby triggering the interior motion sensors. These sensors can even be triggered by leaving the window open on a windy day.
If you disable the interior motion sensors for a few days or a week and the alarm stops going off – you know that the alarm issue was related to the interior motion sensor being triggered.
You can also fumigate your Jeep with bug spray and hopefully that’ll make sure there aren’t any bugs left.
Here’s what owners on jeepgarage.org had to say:
“Also understand that if your build has ultrasonics inside, bugs can trigger the system. Flies, mosquitos, midgies, etc. I disable the alarm when camping.”
“The reasons the alarm is going off is it has Ultrasonic sensors near the rearview mirror. People or animals in the car will set it off, as will leaving the windows down on a windy day. If it is a regularly random false alarm, then the hood switch seems to be a regular problem.”
How To Disable Jeep Grand Cherokee Interior Motion Sensors
On a number of Jeep models you can disable the interior motion sensors by pressing the key lock button 3 times in quick succession on the fob. Some owners recommend pressing 4 times, just don’t do it too fast.
However, this will really depend on your model year, so the best thing to do is to consult your owners manual, and also double check that you have motion sensors installed.
Tip: If you can find an online PDF version try using the search shortcut Ctrl+F and typing “interior sensor” to locate the information you are looking for faster.
3. Ensure All Doors & Windows Are Closed (Including Rear Glass)
An often overlooked reason why an alarm goes off at random on a Jeep Grand Cherokee is due to a door or window not being shut properly.
Its a good idea to give all latches a good clean and a spray with WD40, you can work the WD40 in by opening and closing the door.
Here’s what owners on jeepgarage.org had to say:
“Check all the doors/windows that could set it off to make sure they are solidly closed. I recall reading about people who couldn’t get the rear hatch to go up and thought there was a problem with the lift mechanism but it turned out the rear glass was not completely closed. If it’s “partially” closed then all it may take is a breeze or a heavy vehicle driving by to move it and set off the alarm”
“After opening and reclosing all doors, liftgate and flipper glass, no further alarms so far. I’ll keep my fingers crossed. Mine turned off with just pressing the unlock button on the fob.”
“Ditto with the sunroof left open!”
4. Software Update Required
A number of Jeep Grand Cherokee owners have reported that by taking their vehicle to the dealer and having the software updated (flashing) the false alarms went away.
If you suspect your car needs a software update, speak with your local Jeep dealer.
Here’s what Grand Cherokee owners on jeepgarage.org had to say:
“Don’t panic. A simple ECU Flash/Update by the dealer will correct the issue.”
“Well, went to the dealer and had the TSB/Flash/Update done this morning. I read through the TSB thoroughly before going. It gives very clear step by step directions to the tech and clearly tells him what “codes” to look for to confirm that the TSB will apply and be the correct fix for the problem…
…Truck’s been sitting all day with the alarm “armed”, and so far, so good……no false alarms”
“So just take it to your nearest Jeep dealer and have them flash it per the TSB that has been out for months and you will be all set.”
“Thanks! That was it. A Flash/Update was performed which updated several points. Not only corrected the alarm issue but preventative of other issues that may have come up. I’m a happy camper!”
5. Accidental Press Of Panic Alarm On Fob
A simple yet common cause of the Jeep GC being triggered mysteriously is accidental pressing of the panic alarm on the key fob.
On most GC models you can silence the panic alarm by pressing the panic alarm button again.
On jeepgarage.org here is what owners had to say:
“Mine went off the other day. But I THINK I bumped the panic button cause I was carrying my kids child seat and it probably bumped it on my pocket.”
Similarly, here’s what owners on jeepcherokeeclub.com had to say:
“You accidentally hit the Panic button on the key fob, most likely. Happened to me once early on and I had no idea what was going on. Regardless if that’s the case, hitting the Panic button while the alarm is going should turn it off.”
“It seems to be a relatively common occurrence. I’ve had it happen twice. The first similar to yours; “What is happening?!?!? Make it stop!” Seems like a poor design in the fob that there is nothing protecting the button (like a ridge) from being inadvertently pushed.”
“I had this happen twice. Once when getting into the car and the fob in my pockets brushed against the bottom of the steering wheel. Should be designed that panic button needs to be hit twice to set off alarm.
6. Battery Terminals Not Tight Or Dirty
A number of Grand Cherokee owners have stated that the cause of their false alarms was in fact loose 12V battery connections or dirty 12V battery connections.
To rule out this possible cause, give your 12V battery a good clean.
Remove the connections first, and ensure the engine is turned off.
You can use a toothbrush and some baking soda mixed with water –
Once your battery is clean make sure the connection are tight
Here’s what GC owners had to say on cargurus.com:
“Had the problem of intermittent unnecessary alarm. Opened both the terminals of battery and cleaned, waited for 3 minutes, reconnected and started. Run 40 Kms. No alarm! May be due to the terminals were not conducting properly, due to corrosion/ unclean surface.”
“That worked! Cleaned off and tightened terminals and the car now unlocks without tripping the alarm. Thanks to whoever came up with this.”
“Had same issue with my 2004 Jeep Liberty. I read disconnecting battery for a few minutes and reconnected resets system. It worked for me!”
7. Weak 12V Battery
Another common cause of false alarms on Jeep GC is a weak 12V battery. To rule out this possible cause simply test your battery (we’ve included a short guide at the end of this article) or have a mechanic do it for you. AutoZone offers free battery health checks.
Under normal usage, a 12V car battery should last roughly 3-5 years.
If you have had the battery for a long time then it might be time for a replacement.
8. Key Fob Issues
A key fob that is dirty, faulty, or most commonly, has a low battery can lead to the Grand Cherokee alarm going off at random.
We suggest cleaning the inside of the fob with some rubbing alcohol and a cotton swab and replacing the battery as a first course of action.
If you have a second key fob you can clean it and change the battery also.
9. Faulty Door Switches
Faulty door switches are another reason why the alarm on your Jeep GC may go off at random. The door switches monitor whether or not the door is open or closed, if they are dirty or faulty they can send false readings.
For example, when the car is locked and the alarm is armed, the door should be shut. If the switch sends a message that the door is open, the alarm will be set off.
If you suspect you have a faulty door switch, take your GC to your nearest Jeep dealer and ask them to run some diagnostic testing to pinpoint the faulty door switch.
10. Aftermarket Alarms
If your Jeep has an aftermarket alarm fitted (one that did not come fitted as standard) then this may have been incorrectly installed or it may be faulty.
It may also have additional sensors which might be damaged or overly sensitive.
Aftermarket alarm systems are often more sophisticated than a typical factory-installed car alarm but are often installed by people who aren’t mechanics.
If you have an aftermarket alarm that’s causing you problems it’s best to have it examined by your nearest Jeep dealership or an auto electrician.
11. Damaged Wiring
Damaged electrical wiring can cause a wide variety of issues, especially with the alarm system.
Damaged, corroded or faulty wires aren’t easy to find and you’ll need to have an auto electrician carry out some fault finding on your car.
A common point of failure for electrical wiring is in and around the doors,.
If you’ve had some kind of water leak in your car then this issue is one to investigate.
Check for Recalls or TSBs
By entering your car’s VIN number on Jeep’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 Jeep Dealership
If needed, take your Jeep 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.