Help! 1987 Corvette Z51 4+3 overdrive help please...

[vettebob]

Man, I hope somebody can help me with this.... I have been web/forum searching for hours and can't find it. Trying to get this '87 Vette ready for a trip asap. My books don't have the correct wiring diagram and I can't find it on the net.

I want to convert my 4 + 3 to a manually switched operation. (By pass the computer.)

I have seen it said many times to just cut the tan/black wire at the relay and run it to a switched ground. But here's my problem. My relay has TWO separate tan/black wires going into the relay.

Here's the wires on the relay connector:

Brown (verified goes to ALDL)
Pink w/black stripe (Assumed to be power, and has 12v with key on.)
Two Bluish Green wires together on same terminal. (Go to O.D.)
TWO separate tan/w black stripe wires. ??? (These both have 12v with key on.)

So how do I bypass the computer with this setup?? I don't dare take a chance on frying the computer.... budget is shot from other fix ups and repairs!

Thanks!
vettebob

 

[vetteoz]

My books don't have the correct wiring diagram and I can't find it on the net.

Not much help with the colors you have but this is how it is supposed to be

Terminals C and E should have 12V power
B should operate the relay by going to earth
A should be the output to trans and O/d light
D is the test terminal to ALDL

 

[vettebob]

Ok, thanks. I'm not sure why my colors are whacky either, but with this diagram you have provided I have more to work with tomorrow.

My dash display goes so dim you can't see it when I turn my headlights on. It brightens and dims normally, except when you turn the headlights on and then they go super dim. Rotating the headlight switch dimmer makes no difference. If you shine a flashlight into the photocell, they brighten right up, but take the flashlight away and they go too dim to see again. Any ideas on that one??

Thanks again,
vettebob

 

[G Winter]

Are you sure your tail lights are working . Dash and tail work on same fuse.
If the dash is just dim I am not sure but if it is totally dark check the taillight fuse.

Glenn

 

[vettebob]

Dim Dash...

Hi,

Yep, the tail lights work fine, and the instrument panel works perfectly until you turn on the head lights. It is bright in sunlight, and dimmer after dark. And the photocell is reactive to having a flashlight shone on it. BUT, if you turn the headlights on the panel gets really dim. Shine a flashlight on the photocell and they brighten right up, even with the headlights on.

The previous owner actually had a small light attached so that it would shine on the photocell to brighten the panel for night driving!!

vettebob

 

[vettebob]

Overdrive plus dash problem...

Hi,

Thanks for the input, and I have solved the O.D. setup problem.

I also solved the "dash lights going too dim with headlights on" problem by disconnecting the C6 wire on the 32 wire connector going to the instrument cluster. The lights now dim according to ambient light, but are not affected by turning the headlights on.

Thanks again,
vettebob