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Maintenance / Re: Alternator not charging/ starter switch ground
« on: April 12, 2022, 02:14:56 AM »
Here's a couple of pics that might help from the Chassis Service Manual. I notice you didn't mention the junction block on the radiator support, which supplies voltage from the alternator back into the battery. Check the voltage at that point with the car running, might give you a clue as to what the battery is seeing in terms of voltage. Also check the voltage output at the back of the alternator, should be 14.25 volts at about 1700-2000 rpm. If not, I'd suspect another problem to be the alternator.
12.6 volts on the battery is fully charged (as you noted), anything below 12.2 is considered discharged (although you can still likely start the engine). Your ignition switch should have 7 wires on it, I susoect the 20 guage black wire (6 o'clock position on the switch here in the wiring diagram) is the one you are missing ? That shouldn't have an impact on the charging system in my estimation. I meant also to ask if the wiring at the voltage regulator has been re-assigned, or is the original harness intact ?
Don't laugh too much, but I recently discovered the prudence of carrying a battery jumper with me, due to a failed battery on my wife's Tahoe when we least expected or needed it. I borrowed an Imazing jumper from a kindly Samaritan in the parking lot, and cranked it right up. Battery showed 10.3 volts, new GM electronics won't start with that kind of voltage. I did, however, get a text from Onstar about 15 minutes later that my battery was low, and to start the vehicle immediately. Honest -
Regards,
Steve
12.6 volts on the battery is fully charged (as you noted), anything below 12.2 is considered discharged (although you can still likely start the engine). Your ignition switch should have 7 wires on it, I susoect the 20 guage black wire (6 o'clock position on the switch here in the wiring diagram) is the one you are missing ? That shouldn't have an impact on the charging system in my estimation. I meant also to ask if the wiring at the voltage regulator has been re-assigned, or is the original harness intact ?
Don't laugh too much, but I recently discovered the prudence of carrying a battery jumper with me, due to a failed battery on my wife's Tahoe when we least expected or needed it. I borrowed an Imazing jumper from a kindly Samaritan in the parking lot, and cranked it right up. Battery showed 10.3 volts, new GM electronics won't start with that kind of voltage. I did, however, get a text from Onstar about 15 minutes later that my battery was low, and to start the vehicle immediately. Honest -
Regards,
Steve