Battery Drain 1995 Lesabre

[tcassem]

Friends car battery goes dead after sitting overnight. New battery, alternator checked out. Where do I start? Obviously something is draining the power. Will a code reader catch this?

tc

[yogi_123rd]

To find out which circuit the problem is in:

1. Remove negative cable from battery.
2. Attach a voltmeter between the detached cable and the negative battery post. A voltage reading indicates a power drain from the mystery circuit.
3. One at a time, pull the fuses and check the volt meter. When you remove the fuse of the problem circuit, voltage goes to zero.

[tcassem]

thanks yogi, I will try this. What scale should I be on concerning the voltmeter? I'm not real good with electrical stuff.

Terry

[yogi_123rd]

0-12 volts.

[tcassem]

Ok, i pulled all the fuses under the dash and all the maxi fuses under the hood. Voltmeter never went to 0. I'm using an ohm/volt meter set on the DC-v scale. The scale has increments of 1, 3, 10, 30, 100, 300. on the 30 scale I get a reading of 3.5. The negative lead is touching the negative terminal on the battery and the positive lead is touching the negative battery wire. In other words the meter is between the battery and negative power wire. Is this sound right?

[yogi_123rd]

Sounds like you did everything correct.

If pulling fuses didn't locate it, then the drain could be a bad alternator (i.e. a circuit with no fuse). You can check that possibility out by disconnecting the power wire at the alternator and re-testing for voltage thru the negative cable as before.

If this fails to be the problem, I'd be almost stumped. You would be looking for a circuit with fusable links (hot wires designed to melt like a fuse) instead of a circuit using a fuse. You would really need a wiring diagram to find them. I assume nothing obvious is running on after the ignition is turned off. to give you a clue (like the AC/Heater motor).

[tcassem]

I hooked up a cheap craftsman volt meter in line as before it reads 11 volts. Nothing is running or turned on in the vehicle. I also have already disconnected the alternator wire to see if the voltage would drop but still the same. How about the starter wire? or pulling all the relays one at a time?

[buickmastermind]

Just for kicks and grins, see if your hood has a lamp on it and check to see if it is still on while you are trying to take the readings. In which case, at night see if it stays on even when the hood is closed. Not really sure if yours had a lamp under the hood, but my '86 does. If that is the problem, simply take the bulb out until you can check the wiring diagrams.

[tcassem]

I will check but I'm fairly sure the light is not on. In fact the light does not come on when the hood is up unless the parking lights are on. When reconnecting the negative lead to the battery I get a lot of contact sparks. Something is draining serious power. I also have disconnected the regulator wire with no improvement.

I'm getting tired of this problem.

[johnes50]

Did you ever solve your battery drain problem? I have the same problem with my '92 LeSabre. I had the alternator and battery tested. The alternator is bad, but the battery is good. An aditional problem I have is that the ignition switch won't turn to run.
John S.