My GMC Sierra Pickup Has 20,000 Miles, and It Won’t Start, My New Battery Is Dead and the Dealer Says They Can’t Fix It

If you can't fix my truck, who can?

That's what a GMC Sierra pickup owner asked the dealer after they said they couldn't fix his truck.

The owner of this Sierra 1500 pickup took it to the GMC dealer, where he bought the truck, but they could not fix it. It's not a good situation he finds himself in. If the dealer can't fix it, who can? 

Imagine the frustration of this GMC Sierra truck owner with the dealer. It's been in the shop for what feels like an eternity. The GMC dealer is unable to find a solution to the truck's persistent battery drain. He pushes on the push button start, and nothing. 

The dealer installed a new battery and checked every connection and cable, and your truck is still dead. After installing the new battery, they push the start button, and there is still nothing. The truck has a battery drain or a loose connection somewhere, but they can't find where it is.

The GMC tech hooked up his onboard diagnostics (OBD) system to the truck's computer to see what was happening. The lights across the display screen are all red except one. The tech has never seen any reading like this before. It doesn't make sense.

The problem is a head-scratcher. 

It's the second time the truck has been in the GMC dealer's shop without a solution to the Sierra's battery problem. The owner had the truck at the body shop earlier due to a collision, and the windshield had to be replaced. Other than that, there was only minor damage to the pickup. 

Everyone is stumped.

The GMC dealer has no option but to call a tech who has diagnosed other complex issues. 

With the right information and knowledge, what appears unfixable can be fixed. The service manager calls the tech and says, "We'll send the truck over; good luck."

Menjicar (@menjicar), a Master Tech in California, gets the truck in his shop and goes to work.

Menjicar says, "It's a newer GMC Sierra pickup, and they (the GMC dealer) are paying me a crazy amount of money to fix it. It only has 20,000 miles, and the dealer doesn't know how to fix it."

"The problem with the truck is that the battery is dead when you try to start it. The battery keeps draining for no reason. Several mechanics have looked at it and can't figure it out." 

Menjicar points to the diagnostic computer he has connected to the Sierra truck. 

"The biggest issue we have going on here is there is absolutely zero communication going on here with any module except for this green on right here. I've checked every fuse and every feed under the hood." 

"I can definitely tell that someone has been here or several techs because all these protective covers are loose, and a new battery has even been installed." 

"This truck has been in an accident, so I'm definitely checking the wiring. The wiring looks good to me," he says, pointing to the wiring near the new battery.

The Master Tech gets back inside the truck. He looks at the windshield and sees that it has been replaced recently.  

"As I look at the windshield, I notice an issue. This right here (pointing to a different glass manufacturer than the original OEM) shows that the windshield has been replaced." 

The master tech looks at the inside of the windshield and points out a problem. 

"Whoever replaced the windshield could have possibly damaged or cut the wires here," he says as he points below the rearview mirror. 

"This is a radar camera, and it's absolutely crazy. I was inspecting the wiring that goes along the windshield and the wires to the radar camera, and this always gets pulled out when the windshield is replaced." 

"Looking right here, I can see that the wires on the camera have been disconnected."  

Menjicar then connected the wires to the correct position and pushed the truck's push button to start, and the truck started immediately. "That's crazy," he says. He points back to his diagnostic screen, too, and shows that now the screen shows that all the codes are connecting.

"I scanned the codes again; sure enough, we now communicate with everything. I have to clear the codes here; sure enough, all the codes are lit up green. It's time to go collect some money."

The Master Tech made it look easy. 

What is a Master Tech?

The ASE says, "Master Technician status is earned when you achieve certification in all required testing areas for that series. For example, technicians certified in tests A1 through A8 are Master Automobile Technicians. Those certified in tests T2 through T8 are Master Medium/Heavy Truck Technicians, and so forth." 

However, ASE says that Master Technician status is not for life. "You must keep each one of those certifications current to maintain Master Technician status. If you lose Master Technician status due to the lapse of one or more required certifications, it can be reinstated by taking and passing the Recertification Tests."

Conclusion.

With this GMC Sierra pickup, it took the right mechanic to figure out this head-scratching job. It took the Master Tech only a few minutes to figure out the problem that had the GMC dealer techs stumped for days. They never did figure it out.  

A problem that could have cost thousands needed a new perspective. Now, the dealer has to pay their master tech big bucks to get the job done. We haven't been told what Menjicar charged the GMC dealer, but it must have been significant.  

We also haven't been told what the dealer charged this GMC Sierra owner. If they were smart, they charged him for the new battery plus labor and ate the rest. 

The owner of the Sierra pickup must have felt a wave of relief and satisfaction when his truck finally started.

Sometimes, an unsolvable problem can be solved by someone with experience. This GMC dealer will likely be calling Menjicar again.

Have you had an unfixable problem with your GMC Sierra or another vehicle? If so, click the red Add New Comment link below and let us know.

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I am Denis Flierl, a Senior Torque News Reporter since 2012. My 30+ year tenure in the automotive industry, initially in a consulting role with every major car brand and later as a freelance journalist test-driving new vehicles, has equipped me with a wealth of knowledge. I specialize in reporting the latest automotive news and providing expert analysis on Subaru, which you'll find here, ensuring that you, as a reader, are always well-informed and up-to-date. Follow me on my X SubaruReport, All Subaru, WRXSTI, @DenisFlierl, Facebook, and Instagram.

Photo credit: Denis Flierl via GMC and Menjicar