GMC Savana Battery Issue Goes Beyond Dead Battery

I dealt with nearly identical symptoms on my 2012 GMC Sierra diesel last winter. As someone with some hands-on experience maintaining vehicles, I first suspected a simple discharged battery case too. After multiple attempts to charge the battery and cleaning the battery terminals, the issues persisted. The workshop diagnosed a faulty battery sensor, which was causing incorrect readings and leading to battery drain issues. The repair, including diagnosis and replacement, cost 315 Euro. The battery sensor monitors charging status and power distribution. When defective, it can trigger various electrical issues like yours, dashboard errors, weak lights, and starting problems. The stored error codes were a big clue that this wasnt just a standard dead battery situation. To better assist with your specific case, could you share: Has your battery been replaced recently? Are the issues constant or intermittent? Do you notice these problems more after short trips or long parking periods? What error codes did the workshop find? This information would help determine if youre dealing with a similar battery sensor failure or perhaps a different electrical issue.

Last service was at 74150 KM, about 2 months ago. The battery terminals look clean, but the workshop found a mix of issues. The alternator tested fine, but it seems the battery drain continued even with the vehicle off. After cleaning connections and running tests, we discovered the vehicle battery was draining through the radio circuit. A faulty ground connection caused the system to stay partially active. The constant power draw led to the discharged battery and triggered those error codes. Current readings from the workshop show 0.8A drain, which is too high for a parked vehicle. Need to track down where exactly in the radio circuit this drain is happening.

Thanks for the update on your GMC. That 0.8A battery drain is definitely concerning, for comparison, my Sierra showed a 0.05A draw when I had the battery sensor issue. When tracking down my electrical problems, I also initially suspected the radio circuit. However, the diagnostic path revealed the faulty battery sensor was the root cause. Your situation sounds more like a genuine parasitic draw through the radio system. A few things worth checking based on my experience: Test the radio ground connections at multiple points, Verify if aftermarket accessories were added to the radio circuit, Check if battery drain occurs with radio fuse removed, Monitor drain levels after extended parking periods The workshop measurements align with a significant parasitic draw. Normal battery drain should be under 0.05A when parked. Your 0.8A reading explains the battery failure symptoms, that level of constant draw would discharge even a healthy battery within days. This appears more complex than my sensor issue, but the core problem of battery drain needs addressing before replacing any components. Otherwise youll likely face repeated battery discharge issues.

Thanks everyone for the input, I think we've found the culprit. After more testing, the radio's constant power draw was traced to a corroded ground wire behind the head unit. The workshop found the wire had been rubbing against a metal bracket, wearing through the insulation over time. The repair was straightforward, replaced the damaged ground wire, secured it properly, and added protective sleeve. Total cost was 85 Euro for parts and labor. Vehicle battery charging restored normal voltage after fixing the ground connection. After a week of monitoring, the battery drain dropped to 0.03A when parked, much better than the previous 0.8A draw. All electrical systems now work normally, no more error codes or flickering lights. Starting is strong and consistent. This experience shows how a simple ground issue can cascade into what seems like major electrical problems. What looked like potential alternator or battery sensor failure turned out to be basic wire damage causing battery drain. Glad I investigated further before replacing major components.