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o/d electrical problem

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Old Sep 30, 2011 | 12:45 PM
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justin_heat05's Avatar
justin_heat05
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Default o/d electrical problem

1987 corvette 4+3 trans standard

I ran a 12v switch to my o/d plug-in and now overdrive works. So there must be an electrical problem.

Where should i start first? I already checked the switch on the gear shift, everything is fine with it. I read something about a relay may be the problem.

Where is the relay located?

This car has been wired on and worked on before. If i can't find the problem, is it okay if I bypass it with a 12v switch that is fused and run off of a hot wire that loses fire when the car is turned off? Has anyone done this?
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Old Sep 30, 2011 | 01:47 PM
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From: Naples Campania
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It's either the switch or the relay. Are there codes for this? Does anything test the OD relay?

Anyways...


I don't know how you would test the switch, but...

Here it is.

If someone knows if you can T/S this, I would do it before you purchase anything.
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Old Sep 30, 2011 | 08:30 PM
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Originally Posted by navy_vette
It's either the switch or the relay. Are there codes for this?
Switch doesn't operate the O/d .It only sends a signal to the ECM to do so.
If everything in place and working O/d will operate automatically with out driver input.
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Old Sep 30, 2011 | 08:32 PM
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Originally Posted by justin_heat05
If i can't find the problem, is it okay if I bypass it with a 12v switch that is fused Has anyone done this?

Also you have a 1st gear lockout switch at the trans that is part of the O/d circuit.
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Old Oct 1, 2011 | 08:28 AM
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Test your gauges fuse, if you haven't done so already.

Some help from my 86 FSM

http://members.shaw.ca/agent86/Overdrive-manual.pdf
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Old Oct 1, 2011 | 10:06 PM
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thanks for all the help guys
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