Reader Question: I have a 1992 Buick Regal with approximately 40,000 miles. It had a new alternator installed about 10 months ago. Within the last three months, it has randomly not started in the morning because of a dead battery.
It will start fine for several days and then out of the blue it is dead. (really dead! no interior lights or gauges). I have to put a charger on it to start it. It will then start fine again for a couple of days.
The mechanic that has looked at it cannot figure it out. He has kept the car for several days to drive it. It has yet to go dead in his yard. After each time he drove it he checked to see if there was a draw on the battery. Nothing has shown up.
Do you have any suggestions on what this could be?
You might want to try another mechanic and have them start from scratch. They should do a complete electrical test, which should include the following:
1. Load test the battery – can the battery hold a charge?
2. Check alternator output – is the alternator recharging the battery properly?
3. Check for a voltage drain – is something ON when it should be OFF – are the doors closing properly and not leaving the interior dome light on sometimes, check hood and trunk and glove box lights to make sure they are not ON.
I have seen electric antennas and electric seat motors stay ON overnight and run batteries down. You can stay inside the car with the engine off and key out of the ignition and LISTEN for anything that might be running.
4. Check the battery connections – those small metal GM battery bolts are notorious for coming loose and building up corrosion between the battery cable and the battery. You should not be able to easily move the battery cables with your bare hands.
We charge $48 for this test at my shop. You might be able to find a starter/alternator re-builder in your area to do it cheaper and while you wait?