1997 850 Wagon voltage drain?

Tobers · Post by **Tobers** » 22 Dec 2014, 09:24

My daughter's 850 wagon didn't start today after sitting for 3 days. I measured across the terminals and it read 12v. I jumped it. I measured it while is was running: 14.2. The battery is just a year old. I turned the car off, disconnected the positive cable and put a multimeter between the cable and the positive terminal. It measured 15 on the "200Vdc" setting. I don't know what that number means, so I pulled every fuse, hoping to make this number go to "0" but it always measured 15. After a few minutes it measured 12.

What should I do next? Please advise. Merry Christmas. And, thanks. Rick

draser · Post by **draser** » 22 Dec 2014, 12:43

You tried to measure current with meter on volt scale and it will not work. Need to set meter on Amp scale, biggest the meter has, probably 20 amps. Have positive lead on positive post. Then you'll measure residual current like intended. Pullings fuses will id the problem circuit. Voltage measurements of 14.2 while running shows good chargi g circuit, bat should show about 12.6 when fully charged. You're on the right track.

Post by **rspi** » 22 Dec 2014, 14:16

Most common drain is the glove box. Toss a camera phone in there and see if it is on with the door closed.

Post by **jgc470** » 22 Dec 2014, 14:35

I went thru the dead battery issue about 6 months ago on my 96 850. I not sure a current read is the best approach. There are three likely sources of such potential problems: alternator (not charging enough), cables and their connectors, the system (lights, alarm, lock set, which is my problem turned out to be my issue). If your battery has 12v across it, and 14.2v in operation, then that suggest to me cables/connector or electrical system.

The cheapest is check you battery connector make sure it is clean, then look at the negative cable connection to see if that is clean. I loosen my connection, wiped it clean and gently sanded it. Also another check, the main battery wires will age and deteriorate. This will increase the resistance of the wire and when the system is running the battery never fully charges as it should because the resistance of it is greater than it should be.

After that I went go to fuse system and, one by one, found my problem to be #15, which connects to grove box light, dome light, and keyless entry. I replaced keyless entry. Good luck.

Post by **jgc470** » 22 Dec 2014, 14:57

addendum: .., a forum member used IR gun to detect any excess heat from the negative cable, but if that's the issue, I think it would feel warm to the touch,

Tobers · Post by **Tobers** » 22 Dec 2014, 15:52

Thanks so much! I think it's solved, but we'll see. Draser was right: I was using the multimeter wrongly. Once I came to that conclusion I slowly and painfully discovered the fuses were blown in it (I'm sure I did it). After a couple of failed hours looking for new fuses, I bought another multimeter. Once I was using it correctly I found out that there there was amperage drain from fuse 15, and the guilty culprit (so it seems) was the glove box light. Disconnected it. Looks good on the meter, but time will tell. Thank you! (ps If you have a Craftsman multimeter, don't expect to find a fuse anywhere easily. Of course, if you don't blow them like I did, then you won't have this problem ...)

Post by **E Showell** » 23 Dec 2014, 12:32

Craftsman -- shouldn't Sears simply replace it?