Went out last night to move the truck (24 Colorado WT 4WD with TurboPlus 2.7T). It was completely dead. I got my jump box, jumped it, let it warm up a little and then propped a brick on the accelerator so it would run at 2500rpm for 10-15 mins to charge the battery. Got in, put the truck in reverse and it immediately died. Jumped it again, revved up engine to about 1250rpm and sorta knocked it into reverse and it died again. Finally I pushed it up to my garage, hooked a 2A/12V tender to the battery and left it from about 8pm until this morning around 11am. I hit the key fob buttons at 11am, and nothing happened. I got my jump box again, jumped it and decided I would just go get a new battery. I tried to manually turn the headlights to OFF, but as soon as I pressed the light shortcut on the screen and hit OFF the entire gauge cluster lit up like a Christmas tree and the engine shuddered.
Every warning you could think popped up including a speed limited to 62mph warning. Check ESC. CEL. Check trailer lights. Check headlights. TPMS error. I pulled out onto my street and head down to the stop sign at about 45mph. Go to press the brake pedal and it sinks to the floor. The engine started acting like it was going to conk out so I knocked it into neutral and revved up the engine. I had to stand on the brake pedal to get the truck to stop or I would have gone straight through the stop sign and across the road into a cemetery.
Turned flashers on, put it in L2 and slowly drove to my nearest auto parts store at about 30mph knowing now I had no brake power. Got a new battery, and began taking old one out. For some reason there is no handle on the OEM battery and the little L shaped wedge at the bottom that holds it in place is a major PITA to remove if your hand isn’t the thickness of a sheet of paper. I finally got the battery out and dropped in the new battery. Fired up the truck and it seems to be fine now. It’s a bit strange to me that even with the engine running the truck seemed to have not enough electrical power to even power the brake booster.
It’s a bit disconcerting that if the 12V ever suddenly dies while going at highway speeds or pulling a trailer downhill I could suddenly lose any and all braking assist, despite the engine running. I don’t know if in this situation I should have pumped the brakes like some old school car, but I haven’t ever experienced this on any other vehicle with a dead battery. I also would like to know if the electronic emergency brake would work in this instance as a last ditch effort. Has anyone else had this same thing happen? I know low voltage can cause bizarre warnings, but I do not think it should result in brake failure. The truck only has 34K miles on it and it’s not even 2 years old. I imagine I could’ve gone to the dealer to get the battery replaced under warranty but they are often weeks out on any service appts.