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Volkswagen Rabbit, Jetta, Scirocco, Convertible: 1975-1984 (A1) 84 rabbit GL dash oil light on when car is off/dead battery


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Last Post: Jul 27, 2010 6:31 PM Last Post By: tcovenant2000
jaytee601

Posts: 2
Registered: 07/22/10
84 rabbit GL dash oil light on when car is off/dead battery
Posted: Jul 22, 2010 1:58 AM
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Here's to letting a helping hand jump start my rabbit!
The other day I left my direct radiator fan switch on by mistake until my battery died. When I asked a buddy for a jump, my friend didn't realize that he had the jumper cables on my rabbit's battery on backwards. After realizing what had happened, we were able to switch the jump cables to their correct position and gave my rabbit a jump, however as soon as we took off the cables, my rabbit died. I bought a new battery and installed it. My rabbit cranked right up and was able to make it home, however when I turned off the car ad took my keys out of the ignition, I noticed that the oil light on the dash was dimmly lit. Next morning, my rabbit was completely dead again. No oil light, no nothing. When I place the cables on to jump start the car, the oil light slowly turned back on during the recharge while the car was off/no keys in the ignition. Once enough juice was running through the battery, I was able to turn the car on, however as soon as I disconnect the jumper cables, the car just died again....

Any suggestions of what could be draining my battery and making the oil light turn on while the car is completely off? I failed to note that when the car starts, the oil light turns off.

Thanks!
tcovenant2000

Posts: 1,360
Registered: 12/09/03
Re: 84 rabbit GL dash oil light on when car is off/dead battery
Posted: Jul 22, 2010 7:31 PM   in response to: jaytee601 in response to: jaytee601
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Where to start?
You probably have fried ground wires. Under the dash is a "ground tree". It's a tree-looking thing with a bunch of brown wires connected to it. Many things ground there.
You've probably fried the lambda controller. Possibly the oil pressure device.
Worst case you've melted wires under the dash and they are shorting together (my son did this with his Jetta).

The best way to find the battery drains is to pull all fuses and get a 100A meter. Put the meter between the + term of the battery and the + cable. Put the fuses back in one at a time and note which ones show current draw on the meter.

It could be very simple...melty ground wires or something...or it could be very bad. Happily there aren't much electronics in that car, as they react poorly to negative voltage. Unhappily, most of your relays have little circuit boards in them and you may have fried some of those as well.

Thomas
jaytee601

Posts: 2
Registered: 07/22/10
Re: 84 rabbit GL dash oil light on when car is off/dead battery
Posted: Jul 25, 2010 11:17 PM   in response to: tcovenant2000 in response to: tcovenant2000
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Thank you for your suggestions. After checking all fuses, I was able to pinpoint the culprit. The power drain was due to a bad alternator. I was able to take it off, double check with my local auto parts store that it was indeed bad. Purchased a new one, along with switching out a new battery under warranty. Reinstalled everything and now my rabbit is purring like never before!

Today is the first day of the install, so I'll update the thread in a couple of weeks for an update.
tcovenant2000

Posts: 1,360
Registered: 12/09/03
Re: 84 rabbit GL dash oil light on when car is off/dead battery
Posted: Jul 27, 2010 6:31 PM   in response to: jaytee601 in response to: jaytee601
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Yay!

By the way...I forgot to mention that the first thing to do is have your alternator tested. The diodes in it don't like reversed voltage and they can short, causing drain and battery death.

:)

Thomas

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