My 2007 Avalanche LT has an odd problem. I'll be driving and everything is fine. The voltmeter shows about 14 volts.
Then, all of a sudden, it feels like I just ran into a really strong headwind and the voltmeter drops to about 12 volts. If I continue driving it will eventually drain the battery and it won't be able to restart.
However, if when that happens, I put it in neutral, turn the ignition off, and then restart, the alternator starts charging again and the voltmeter shows over 14 volts.
I have a new battery (because of this I thought the battery was bad) and I'm now on my 3rd alternator. All 3 did the same thing. All 3 test OK because the alternator always works right after starting the engine.
I've learned that the computer can tell the alternator to stop charging (the alternator has wiring that connects to the computer). I suspect the problem is probably in the computer but I have no idea how to check it. I have no trouble codes.
Any ideas?
Then, all of a sudden, it feels like I just ran into a really strong headwind and the voltmeter drops to about 12 volts. If I continue driving it will eventually drain the battery and it won't be able to restart.
However, if when that happens, I put it in neutral, turn the ignition off, and then restart, the alternator starts charging again and the voltmeter shows over 14 volts.
I have a new battery (because of this I thought the battery was bad) and I'm now on my 3rd alternator. All 3 did the same thing. All 3 test OK because the alternator always works right after starting the engine.
I've learned that the computer can tell the alternator to stop charging (the alternator has wiring that connects to the computer). I suspect the problem is probably in the computer but I have no idea how to check it. I have no trouble codes.
Any ideas?
