1993 Corsica - Rear Defrost

Tiny
DEAMION
  • MEMBER
  • 1993 CHEVROLET CORSICA
Hi, and thanks in advance for the help.
I have a '93 Corsica, 3.1L V6. With About 235,000 Kilomitors. (Canada) But the problem is with the rear defrost. When ever I turn it on, the lights dim, the turn signals start blinking VERY slow, and the heater fan slows down. - Sounds like not enough power from the Alt, or Battery. But I already replaced both with better than average parts. That did lessen the problem a little bit, but I would really like to fix it. I do have one defrost line on the back window that's dead. I know where the brake is in the line. But chose not to fix it until this problem is fixed. One other note this problem has always been there since I bought the car used. I have installed a few small stereo upgrades since then, but the problem is no better or worse. So I'm wondering if it's just a short in the rear defrost.
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Saturday, February 10th, 2007 AT 12:39 PM

6 Replies

Tiny
HRYK2646
  • MEMBER
Sounds like you have a short in the rear defrost to me. If you have no problems when the rear defrost is off, then the short would be in the broken line.
Ray
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Saturday, February 10th, 2007 AT 4:02 PM
Tiny
DEAMION
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Wow I would never guess that one broken "trace" line in the rear defrost grid would cause a short, or major power drain in the rest of the car. I've had many cars with one or two lines on the back window that didn't work, but I've never see this problem before.
Thanks for your input. I'll repair that line in the grid, and test again.

Thanks.
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Tuesday, February 13th, 2007 AT 10:47 AM
Tiny
DEAMION
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Thank you for your help. Sadly the problem didn't go away after I repaired the broken grid line on the back window.

Does anyone know if the '93 Corsica has a relay or other type device I should replace in the rear defrost circuit?

Thanks.
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Saturday, February 17th, 2007 AT 2:57 PM
Tiny
CHEVYII
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Ok I will give iit a shot,
there are only a few items in the whole system,
1. Rear defogger grid which is grounded on the right rear window pillar, make sure there is a ground attached to the pillar and the grid,
2 there is a ground in the lower left engine near the starter solenoid make sure that is grounded
3 the defogger switch itself may be shorting
4 I cant remember if the switch is located on the wiper washer switch or not but it does run in that circuit and that circuit only.
And as far as fuses it would not work if the fuse was blown, you have a short to ground somewhere in the system I have explained, if all grounds are good condemn the switch itself

jim
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Saturday, February 17th, 2007 AT 6:07 PM
Tiny
DEAMION
  • MEMBER
Jim you may have hit the nail on the head with that idea. I really should have tested the grounds before posting. I guess it takes a professional to point you in the right direction.

When I think about it, a bad ground would make sense. The car is getting old, and has been in a few small fender benders (Before I bought it). Put that together and a ground wire could be broken.
Also thanks for the suggestions on where to start looking too.
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Sunday, February 18th, 2007 AT 9:34 PM
Tiny
CHEVYII
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No problem, I listed all of the grounds in the whole defogger circuit so it should be fairly easy and if all is ok it may be the switch

thanks again and good luck, if you need more help let me know

jim
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Sunday, February 18th, 2007 AT 9:40 PM

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