The GMC Yukon is a full-size SUV with a standout exterior and well-appointed interior.
Like many other vehicles, this model can be vulnerable to alarm-related problems.
If your Yukon’s alarm keeps going off, this article will give you the info you need.
Table of Contents
Why Does My GMC Yukon Alarm Keep Going Off?
A GMC Yukon alarm is typically triggered by a faulty door or hood switch. Other common causes include interior motion sensors triggered by bugs, damaged wiring, battery issues, and key fob problems.
1. Faulty Door Switches
When door switches (aka sensors) are damaged, corroded or faulty they can cause the alarm to activate unexpectedly by transmitting inaccurate signals to the alarm system.
The switches are prone to wear and tear due to opening, closing, and slamming of the doors.
The door latches and switches can also accumulate dirt, leading to potential issues. Start by cleaning all door latches thoroughly and applying WD-40 to the latch.
Inspect the wiring that runs from the car’s body to the door for any signs of damage. Typically, this wiring is encased within a flexible hose located on the hinge side of the door.
If you have concerns that the alarm issues could be linked to the door switch, it’s advisable to ask your dealer to conduct a diagnostic test to pinpoint the problem.
“ … Sensors can act up or go at any time. Even on brand new cars.” – NewTahoeYukon.com
“It might be the door latch/switch. Do you ever get a message that a door is open while driving?” – TahoeYukonForum.com
2. Faulty Hood Switch
Similar to the door switch, a malfunctioning hood switch can also cause unwarranted alarm activation.
Usually, this switch is integrated into the hood latch mechanism.
This compact yet crucial electronic device plays a vital role in the vehicle’s alarm system by determining whether the hood is open or closed.
Faults, looseness, or dirt accumulation in the switch can result in incorrect signals being sent to the vehicle’s computer, which in turn can activate the alarm unnecessarily.
- Open the hood and locate the hood switch.
- Check for any clear signs of damage, rust or loose connections.
- Give the hood switch a thorough cleaning (with contact cleaner), as dirt and grime can cause issues.
- With the right tools, you can test the switch with a continuity tester.
If you’re mechanically inclined, consider purchasing a new hood switch online and installing it yourself. Otherwise, it’s recommended to seek help from a local mechanic.
Related: GMC Yukon Beeping Problems? (13 Common Causes)
3. Interior Motion Sensors
On some GMC Yukon models, the vehicle is equipped with interior motion sensors.
These sensors can be triggered by bugs, flying insects, moths etc trapped in the cabin.
They can also be triggered if you leave your dog or kids in the vehicle.
There is a button located in the roof of the vehicle for enabling and disabling the interior alarm.
If you suspect there is a bug in the cabin we suggest using some bug spray in the cabin or opening the doors to allow it to escape.
“To update, I’ve been deactivating the interior motion sensors since and it hasn’t happened again.” – TahoeYukonForum.com
“I have the very same problem. However, mine goes off with vibration, I think… I park my 2018 Denali about 10 yards from a commuter and freight train line. During the week it goes off a couple random times every week. Seems to go away if I turn off the motion sensor for some reason.” – TahoeYukonForum.com
“I had a bug flying around in mine one night, it drove me crazy.” – TahoeYukonForum.com
4. Drained 12V Battery
A depleted 12V battery can cause various problems, such as accidental alarm triggering. And it is a commonly reported cause of nuisance alarms on GMC models, especially in cold weather.
It is recommended to have your battery tested for its condition, a service that is often inexpensive or complimentary at locations like AutoZone.
Alternatively, you can conduct a self-assessment using a multimeter (refer to the guide at the end of the article below).
Typically, a functioning 12V battery should register between 12.6 and 12.8 volts, whereas a failing one will show below 12 volts.
“I have read about this before on the 2015+ and in most instances it was blamed on low battery power, odd as it may seem your battery shouldn’t be going bad already, but just something to take into consideration for whatever it’s worth.” – TahoeYukonForum.com
“Just had our battery replaced and seems to of fixed the issue as well.” – TahoeYukonForum.com
“Had the dealer load check the vehicle battery and it failed, battery replaced. I have now remote started the truck on four consecutive single-digit mornings, and no alarm.” – TahoeYukonForum.com
5. Loose or Bad 12V Battery Connections
Poor connections on the 12V battery can lead to various issues, like the inadvertent triggering of your Yukon’s alarm system.
Over time, dirt or corrosion commonly accumulates on these connections.
Driving regularly can cause the battery terminals to loosen.
Always remember to turn off the engine before doing any battery maintenance.
- Examine the battery for wear, dirt, rust, or corrosion and loose connections.
- Detach the battery, starting by loosening the clamp nuts with a wrench.
- Always disconnect the negative clamp, identified by a ‘-’ sign, first.
- Use a toothbrush soaked in a baking soda and water solution to clean the terminals. Rinse with distilled water and dry thoroughly.
- When reconnecting the battery, make sure the connections are secure and tight.
6. Key Fob Running on Low Battery
Sometimes, alarms go off unexpectedly because the key fob has a low battery. Also, if the fob is dirty, it can cause similar issues.
To fix these problems, clean your key fob inside and put in a new battery. It’s best to use a good-quality 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.
7. Faulty Key Fob
Another identified reason for unwanted alarms on this vehicle is a malfunctioning key fob.
If you have two remotes, consider removing the battery from one and utilizing the other for a period.
If the issues with the alarm persist, even after cleaning the inside of the fob(s) and replacing the battery, it is advisable to consult with your dealer.
8. Rear Defroster Plug Issues
One often overlooked but crucial aspect of GMC vehicles’ alarm systems is its connection to the rear defroster. A GMC owner on TahoeYukonForum.com shared a valuable insight, stating:
“Alright guys… problem solved. The rear defroster plug wasn’t making a connection. It’s part of the alarm system as if someone broke your rear glass.”
This indicates that the alarm system is intricately linked to the functionality of the rear defroster, monitoring it as a security measure against potential break-ins through the rear glass.
For those experiencing unexplained alarm activations, the culprit could be as simple as one of the defroster tabs coming loose—a surprisingly common issue.
The solution? Reattach or fix the defroster tab to restore the connection. The owner further shared their successful experience:
“So, anyone having this issue, it’s to do with one of the defroster tabs falling off, which is pretty common, fix it and the alarm issue goes away… I just did it and over 50 remote starts with the issue and now it’s gone!”
9. Accidentally Pressing the Panic Alarm on Key Fob
Your issue with the alarm could stem from something as straightforward (and easily overlooked) as unintentionally pressing the alarm button on your key fob while it’s in your pocket.
The solution is straightforward – have a dedicated pocket for your car key, separate from objects such as pens, coins, or even other keys.
10. Incorrectly Installed Aftermarket Alarm and Accessories
Incorrect installation or defects in an aftermarket alarm system or accessory are frequent sources of bothersome false 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.
11. Damaged Wiring
Faulty electrical wiring can lead to various issues, and identifying the exact problem can be challenging. You might need to enlist the help of an auto electrician to conduct diagnostic tests.
In some instances, rodents may have chewed through an electrical wire.
12. 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 vehicle.
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.
“No cat or raccoon footprints on the truck either? Could security lights on the house going on and off be setting it off?” – TahoeYukonForum.com
13. Not Closing Doors, Hood, or Trunk 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 vehicle’s alarm.
Alternative Suggestions
Check for Recalls or TSBs
By entering your car’s VIN number on GMC’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 an GMC Dealership
If needed, take your GMC 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.
Sources
- https://cdn.dealereprocess.org/cdn/servicemanuals/gmc/2022-yukon.pdf
- https://cdn.dealereprocess.org/cdn/servicemanuals/gmc/2020-yukon.pdf
- https://www.gmc.com/ownercenter/recalls
