graydawn »

I have a 1997 850 GLT wagon and over the last 4 days my battery has been drained over night three times. Not sure what might be causing it. Any suggestions as to where to start to look. The last two times I have gone out to see if I could hear or see anything running. but no luck!

How to Locate Battery Drain

goober4321 »

Here is a simple solution for this problem if you follow these steps……..

1. Take an ordinary 12V test light
2. Remove the positive battery cable
3. Place the test light between the positive terminal of the battery and the positive cable
4. If the light on the test light lights up you have an offending circuit pulling power.

Here is the cool part…………………
5. Start pulling fuses till the light goes out
6. Read what the “light out” fuse circuit controls

WALLAAAAAAA…………………………….
You found your problem. Fix the issue and you are done and the light on that circuit should go out.

Volgrrr »

The reason for putting the test implement on the positive side is simply this.

Placing the test implement between the positive pole of the battery and the positive battery cable means any current flow leaking to earth (i.e. neutral) has to pass through the test implement.

In a perfect world you should be able to do exactly the same test using the negative side however, earthed connections are notorious for developing open circuits due to loose, broken or dirty connections.

Because the vehicle chassis acts as a common negative pathway that allows current flow to return to the battery, any poor connection creating an open circuit will act, obviously, like a switch, i.e. cutting off current flow, and the test implement will not register any current flow under these conditions.

So, by testing on the negative side of the battery, you are putting all your eggs in the one basket based on the premise all the earthed circuit connections are 100% sound. 

I hope this may be of some assistance to you.

Drain on Battery 1997 850 GLT

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Last Updated on July 20, 2026