91 Regal - parasitic battery drain

[91RegalOwner]

In my 91 buick regal 3.8L sedan I have a parasitic battery drain. I don't leave on any of my lights and it looks like all the trunk and hood lights turn off when the hood/trunk is down.

I have just replaced the ignition switch and the turn signal switch which seemed to help but not resolve the problem. The alternator was replaced a few years ago and does not seem to be the problem.

For some reason my battery keeps draining from 12V in the morning to about 7V around 6pm. This is not consistent though. Sometimes I will not drive the car for a few days and it will drain to 0V and requires CAA to double boost the battery in order for it to get started again.

I don't want to spend a lot of money troubleshooting this or fixing it... but does anyone know if it is possible to make a battery kill switch that shuts off the power at the source whenever i leave the vehicle?

This way I won't need to pinpoint exactly where the issue is.. but I can confidently leave my vehicle for a few days knowing that the battery will still somewhat be near the 12v mark when i return..

Again I'm not a whiz when it comes to electricity so any basic instructions (talk to me like i'm a 2 year old kid!!) will be greatly appreciated.

thanks in advance!!

[HotZ28]

It is very simple to track down a battery drain problem; you first need to see the drain. Your tool could be either a volt meter or you can construct a light bulb with two leads so that it will glow when there's electricity flowing.


Procedure:
1. Disconnect the negative battery cable from the battery.
2. Wire the two leads of either the voltmeter or light bulb tool between the disconnected battery cable and the negative battery post. You should see the battery drain at this time on the voltmeter (or see the light bulb tool lit).
3. Pull the fuses in the car one at a time, and observe if the battery drain stops. When the drain stops, you've found the problem circuit and need to investigate why.
4. If you've pulled all the fuses and saw no change, the problem circuit may be one with no fuse in it like the alternator or starter circuit. You would need to disconnect them manually to test.


I had a car in the shop last week that had the same problem as yours. We checked the battery under load and alternator output and all checked within specification. Using the above procedure, I found the glove box light was staying on all the time. The owner never saw that, because the door was closed. The trunk light and glove box light is like the one in your refrigerator, you don't know if it is working until you open the door!

You can buy battery disconnects, however it would be cheaper and simpler to find where the drain is.

[91RegalOwner]

Thanks for the help. Unfortunately the problem is not consistent which means the voltage does not degrade all the time... I figured at this point buying a battery disconnect is probably my best bet. I found one online for about 50 bucks plus shipping so i'm hoping this will be the last of my dead battery issues!!

Thanks again for all the detailed help.

[raybuick]

Hey regal owner, Do the test like Hot z28 says but set up the test light so you can see it go off when pulling fuses. Meaning hood should be down,doors closed, no key in ignition.I had a problem with the power locks not fully locking killing the battery so pulling the fuse stopped the drain till i fixed the problem door handle. I've also read about some cars with some kind of automatic rear stabilizer suspension staying on draining the battery.Good luck and rid that drain. Rayday