2012 GMC Sierra 1500 Electrical Problems

June 29, 2025, Driving on the St. Francis loop in Amarillo, TX, brake lights start flashing, the warning sounds happening, no brakes. I had already slowed down to 35-45 mph due to road construction ahead. I weaved through the cones and as soon as possible, hit the ditch and then coasted to a stop. (I didn’t think about the emergency brake, in my panic.) I turned the vehicle off and called my husband. I decided that I wasn’t pulled over far enough over in the ditch, so I started the pickup again. The lights and warning signals for the brakes were gone and when I pressed on the brake pedal, there were brakes again. I drove home at 35 mph, knowing I could use the emergency brake at that speed, if needed, and had brakes all the way home. GMC Bender repaired truck. After driving approximately 3 miles since repaired, our daughter took the truck to Grease Monkey. She was at the garage door; employee said the pickup didn't need an oil change. She backed out and didn’t have brakes (no warning lights or sounds) and as the truck continued backing, it hit the Grease Monkey sign at the east end of their lot and broke it, knocked the sign over. An employee walked over to see what happened, she told him that she didn’t have brakes. He sat in the pickup seat and pushed on the brakes and said, yes, you don’t have brakes! The police were called, and the officer who showed up took pictures, gave us his card, talked with my husband and talked to the Grease Monkey boss. August 6, 2025, I called GMC Bender Service Department (11 mins. 8 secs.) I told them what had happened. They sent a tow truck to bring the pickup back to their shop. September 16, 2025, my husband texted me saying GMC Bender said that the pickup shows another EBS Modulator Fault. No new parts… used one would be $1293 installed. A week to get it here, no guarantees. There's more details, but the vehicle cannot be repaired to guarantee brakes will work properly. Please help us know what to do next.

NHTSA ID

11756257

Incident

Jun 29, 2025

Odometer Fraud. The contact purchased a 2012 GMC Sierra 1500. The contact stated that it was discovered that there was a mileage discrepancy. The vehicle was a private sale. At the time of purchase, the mileage was 111,000, and at the time of registration, it was discovered that the mileage was 243,000. The Carfax Report indicated that the vehicle was serviced at 149,000 and 179,000 miles, then registered at 149,000 and 179,000 miles on August 8, 2024. The contact had filed a police report with the Dillon Police Department -Special Ops Police Department.

NHTSA ID

11682085

Incident

Aug 15, 2025

Mileage

243,000 mi

P0521 has been addressed/replaced almost nine (9) times. “Low Oil Pressure-Stop Engine” is another one that is not completely functional. The truck is using oil but we cant find evidence of leakage. Services performed at dealership or certified shop. Troubleshooting was performed, Im told. I cant vouch for the quality of the workmanship. This should not be an issue at this mileage 100,100 ohe hundred thousand miles and oil components going bad is not good. GMC has sold me a truck that needs a new engine component. Please help. Thanks [XXX] INFORMATION REDACTED PURSUANT TO THE FREEDOM OF INFORMATION ACT (FOIA), 5 U.S.C. 552(B)(6)

NHTSA ID

11652682

Incident

Apr 3, 2025

The contact owns a 2012 GMC Sierra 1500. The contact stated that while driving at 70-75 MPH, the vehicle inadvertently lost electrical power for 30 seconds. The traction warning light and other unknown warning lights were illuminated. The contact stated that the failure had been recurring while driving. The dealer and the manufacturer were not notified of the failure. The vehicle was not diagnosed or repaired. The approximate failure mileage was 60,000.

NHTSA ID

11444442

Incident

Apr 20, 2021

Mileage

60,000 mi

LEFT SIDE IMPACT SENSOR LOSES CONNECTIVITY FROM WIRES SHORTING OUT IN DRIVERS HINGE AREA. SERVICE AIR BAG LIGHT COMES ON.

NHTSA ID

11388294

Incident

Jan 1, 2021

Mileage

150,000 mi

TL* THE CONTACT OWNS A 2012 GMC SIERRA 1500. THE CONTACT STATED THAT WHILE DRIVING AT AN UNKNOWN SPEED, THE RPM INCREASED WHILE ATTEMPTING TO DEPRESS THE BRAKE PEDAL. THE CONTACT STATED THAT THE BRAKE PEDAL WAS FIRM. THE GEAR SHIFTER WAS SHIFTED TO NEUTRAL TO SLOW THE VEHICLE. THE CONTACT PULLED OVER TO THE SIDE OF THE ROADWAY, TURNED OFF AND RESTARTED THE VEHICLE AND THE VEHICLE OPERATED AS INTENDED. THE CONTACT STATED THAT SEVERAL WARNING LIGHTS WERE ILLUMINATED. THE CONTACT STATED THAT ON SEVERAL OCCASIONS WHILE DRIVING AT VARIOUS SPEEDS, FRONT AND REAR BRAKES INDEPENDENTLY ACTIVATED. ADDITIONALLY, THE DOOR LATCHES LOCKED AND UNLOCKED INDEPENDENTLY. THE VEHICLE WAS TAKEN TO PAYNE CHEVROLET BUICK GMC (2229 E EXPRESSWAY 83, WESLACO, TX 78599), WHERE THE VEHICLE WAS DIAGNOSED AND THE CONTACT WAS INFORMED THAT THE ABS SPEED SENSOR NEEDED TO BE REPLACED. THE VEHICLE WAS REPAIRED. THE MANUFACTURER WAS NOT MADE AWARE OF THE FAILURE. THE FAILURE MILEAGE WAS 141,000.

NHTSA ID

11329525

Incident

Feb 8, 2018

Mileage

141,000 mi

STARTING ISSUES,IGNITION?DEALERSHIP CANT SEEM TO FIND PROBLEM?HAPPENS NOW AND THEN,SOMETIMES IT WILL START AND THEN TURN OFF.THIS ONLY HAPPENS WHEN TRYING TOO START VEHICLE.

NHTSA ID

11150669

Incident

Nov 7, 2018

TL* THE CONTACT OWNS A 2012 GMC SIERRA 1500. WHILE DRIVING AT VARIOUS SPEEDS, AN ABNORMAL SEWAGE ODOR EMITTED FROM THE AIR CONDITIONING UNIT. THE FAILURE RECURRED NUMEROUS TIMES. THE VEHICLE WAS TAKEN TO A DEALER WHERE IT WAS DIAGNOSED THAT THE CABIN FILTER FAILED AND NEEDED TO BE REPLACED. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE. THE FAILURE MILEAGE WAS APPROXIMATELY 51,000. THE VIN WAS NOT AVAILABLE.

NHTSA ID

10886127

Incident

Jun 28, 2016

Mileage

51,000 mi