Dead since last night. Although the instrument displays inside appear to work fine, locks, windows stereo, auto-beep when keys left in the car when door closed all good, but the car doesn't move when put into gear. A couple days ago the service light was on and then went off on its own. Another odd thing is that it is difficult to turn the power off...the display just comes on again and re-initiates after pushing the power button, but still no movement or power to the wheels. I tried disconnecting the ground from the battery for 30 seconds, ten minutes and 6 hours, reconnecting and still no change in the condition. I called OnStar and the fault is something like, "electrical propulsion battery system not functioning as expected"...not helpful. Got it towed to the dealer tonight.
Charged at a free commercial 40amp charger (Clipper Creek) 2 days ago otherwise nightly 120v house plug in.
switched to 12amp charge rate instead of 8 amp after that 40amp 2hour charge didn't seem to bump the milage range much ( 16 miles added)
System seemed to default back to 8 amp on its own previously. I am pretty sure that the last charge was the first/only charge at the 12amp rate on 120 volt connection. I don't think anything happened on the house side of the charging cable.
For the past 4 nights I have been messing around with the speakers, working on a stereo upgrade. replaced the front speakers. So stereo and dome light powered on intermittently while charging car. Prior to the 2 hours working on the stereo last night, I briefly had the car on the charger after work, and I was able to back it out of the garage. However the night that the car died, the stereo was intermittently on without charging the car. Propulsion battery reads 48 miles.
I unplugged and plugged three multi-wire harnesses looking to see if any of the factory speaker wires ran through them ( two under passenger seat 3 nights ago, and one behind the glove box yesterday). No new connections or wire breaks except for T-ing into the rear speaker wires for speaker level input to line out converter
I drilled a screw hole in the rear interior sheet metal towards the rear bumper and scuffed the paint for ground contact
I connected a wire to the 12v battery and ran power to an amp, powered sub-woofer and line out converter to test out components before install.
The sound was great, except the car was later found to be dead.
I find it hard to believe that messing around with the stereo upgrade could kill the car. I am willing to accept the possibility , perhaps the charge on the 12V system was run down, but it seems unlikely. I am thinking that perhaps I should have put the 12V on a trickle charger before calling the tow truck, but I saw no evidence that the 12V battery was depleted. I am an engineer, and I've done many previous installs, so I am not completely clueless. But in this case, the mystery of the software and this fault make me feel pretty clueless.