2018 GMC Sierra 1500 Electrical System
Owner-reported problems and safety issues filed with NHTSA. Review common failures, severity levels, and complaint trends over time.
Complaint Timeline
Chronological view of owner reports
The contact owns a 2018 GMC Sierra 1500. The contact stated that the battery had been replaced three times since 2018. The vehicle was taken to the dealer; however, the failure was not duplicated. The contact referenced an unknown recall; however, the VIN was not associated with the recall. In addition, the contact stated that the first battery was replaced a month after the vehicle was purchased, and the second battery was replaced three weeks after the first replacement. The contact stated that the third battery was replaced a day after the second battery replacement. The manufacturer was made aware of the failure and a case was filed. The contact was advised to contact the NHTSA Hotline to report the failure. The failure mileage was approximately 36,000.
Apparently, GMC began using soy-based wire coatings approximately 10 years ago. The wiring harness on my vehicle has literally been eaten and destroyed by squirrels causing the entire electrical system to be compromised. Safety features have been especially affected including but not limited to air bags, windows being inoperable, door locks being stuck open or closed without a physical key, stabilitrak system arbitrarily shutting off, and windshield wipers working intermittently. Obviously, these are critical systems for the safe operation of this vehicle for the driver, passenger, and members of the public that share the roads. I have had the main harness repaired at a dealership (paid by insurance) but it remains an ongoing safety and financial issue. The dealership identified other portions of the electrical system still need repair and may further compromise safety. Not only were warning lights activated, approximately 10 in-dash messages were displayed warning of malfunction prior to dealership inspection and partial remediation.
Odometer Fraud. The contact purchased a 2018 GMC Sierra 1500. The contact discovered that there was a mileage discrepancy after the purchase. The vehicle was a private sale. At the time of purchase, the vehicle mileage was 72,000. It was later discovered later that the mileage was 241,556.
Rear sliding window defogger started smoking, filling the cab with smoke
Part # 23337305 OEM Towing Control Module failure. replaced with factory part and unit failed within 60 days.
Noted the rear sliding window did not work. Upon further research and investigation found fuse 2 in the drivers side fuse box popped. Replaced the fuse and did not solve the problem. Further investigation found the harness that controls the rear sliding window and other items was sheared (all 3 wires cut in half). The harness is routed from the inside of the center console, through the drivers side hinge (pinch point where it cut the harness, and to the backside of the center console. Spliced the wires and reconnected confirming the fix to the problem. This issue poses a fire hazard. Recommend a recall to reroute the harness or a form of corrugation to better protect the harness and prevent further issues.
Loss of dash electrical system and service stabillitrac warning came on when power was restored along with service suspension warning light. Headlights flicker and engine starts powering down before power comes back on by itself. If fuse to suspension is pulled or negative is removed and replaced, all warning lights go away.
The main harness under the truck , front to back . There was a separation from the conduit, wires exposed and were arcing. Truck would not start . I have since had it fixed . I just feel truck is not that old , to soon for a problem like this . And it cost a lot of money.
The contact owns a 2018 GMC Sierra 1500. The contact stated while driving approximately 70 MPH, the trailer wiring harness system warning message was illuminated. The vehicle was taken to a local dealer where it was diagnosed with needing the wiring harness replaced; however, the vehicle was not repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 77,000.
BATTERY DIES AFTER 5DAYS OF NOT BEING DRIVEN. BATTERY CONTINUES TO GO DEAD, DEALER STATES NOTHING IS WRONG. NO REPAIRS WERE MADE. STRANDED 5 TIMES WITH A DEAD BATTERY
MY TRUCK LOCKED ITSELF WITH THE ENGINE RUNNING WHEN I WAS PARKED IN THE DRIVEWAY. ALSO HAVE HAD THE BACK DRIVER SIDE WINDOW ROLL ITSELF DOWN PART WAYS WITHOUT ME INITIATING IT. ANOTHER OCCASION I PUT THE TRUCK IN GEAR TO DRIVE POSITION AND THE BRAKE OR SOMETHING HAD IT LOCKED PREVENTING ME FROM MOVING EITHER DIRECTION IE; DRIVE OR REVERSE. WAS THEN PARKED IN HOME GARAGE AND ATTEMPTING TO BACK OUT.
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Quick Summary
The 2018 GMC Sierra 1500 has 11 Electrical System complaints on file. Review the timeline above for detailed owner experiences.