Wiring schematic 1988 corvette

[88kfb]

Have a problem with my third brake light on my 88 convertible. The lights are not coming on. About 2 months ago they quit working so they have been working at one time. Here's what I have:
Changed the bulb in the third brake unit. Tested the lights straigght from the battery, they work. Under dash, pulled third brake light switch. Check with meter, switches off an on. Good switch. Checked connector wiring, the purple wire is going to ground (I believe that the purple wire is common ground on corvettes). The pink wire with black stripe also is going to ground. That, I believe, is the issue. I am trying to trace the wire but have no idea where it goes!! Does anyone know if this wire goes to a fuse box or where I can locate an 1988 wiring diagram to point me to the right direction? I have checked with the other corvette forums but do not have an answer.
I do not really want to take the car to a dealer but that will be my last resort. Any help will be greatly appreciated.

 

[Rob]

Before you go tracing wires, I would actually pick up a third brake light switch for under the dash and try installing it. I've replaced the one on my '90 three times already and it only has 27K miles on it. They are prone to failure and it has something to do with the arm mechanism not making proper contact from what I can tell.

Electrically, it may still function when you're checking it with current, but physically, it may not be functioning properly. Since they are cheap enough and most likely, you'll have to replace it at some point, I would just start there first, but that's my own two cents.

 

[88kfb]

When checking the plug the two wires are both going to ground. The switch is basically an on/off switch.. So if I were to jumper the wires i would guess that that would activate the lights. When I checked the wires, both are going to ground.
My first instinct was to replace the switch but after checking the switch for continuity which was good and then checking to see if there was any voltage to the incoming plug, I pretty well can rule out the switch.
There are two wires, a purple one which I believe is common ground and a pink with a single black stripe. the pink with black stripe I expected to have 12 volts coming in, but it is going straight to ground.
Before I got the car, someone had installed a after market alarm. Really a mess. Pulled al the wires out just to getthem out of the way. I suspect that whoever installed the alarm might have messed up the third brake light wiring.
So I am left to locate a wiring schematic and locate where the wire goes. The purple wire appears to connect to a bunch of other wires and then connect to a common ground.
Anyone have any idea where I can get a schematic for an 88 corvette.
Thanks in advance...

 

[Robert Nicodemus]

Scematic

When I ordered a shop manual from Helm, Inc. they threw one in
I don,t know if it's relevant to your year but if not I would contact them. Mine came in the form of a supplement.
Good Luck!!!!!!

 

[Baldie88]

I just purchased the 88 service manual and electrical supplement off of ebay. I'll look tonight when I get home and see if I can scan the appropriate pages you need. In the mean time you might try ebay. I seemed to see the manuals all the time. Most ran up to $80 (new is $128) but I got mine for $60. I'll try and get back with you tomorrow.

Baldie88

 

[Magmotor]

Baldie88,
Could you send me that link where you bought the manual. I'd like to see if I can find one for my '89 without having to go to every vette store on e-bay and look for one...Thanks...!!

88kfb,
I've got the schmeatics on my '89 coupe but don't think they're the same..the purple wires on mine are going to the fog lights. I'm sure Baldie88 has the answer for ya.....

 

[Baldie88]

magmotor - you've got mail.

88kfb - I'm researching the wiring diagrams and will email you shortly.

Baldie88

 

[Baldie88]

88kbf - You've got mail.

Baldie88

 

[88kfb]

Thanks to everyone for the help. So far this is what I have:
I have determined that I have pulled the wrong switch. Looks like I have pulled the TCC switch. Well, it was a second switch!! Looks like the main switch has both the outside and the middle light switches!!!
Feel kinda' stupid to have pulled the wrong switch but what do I know!!
Anyway, I am going to pull the switch and see what I am up against. I will more than likely buy one from the auto parts store and buy one. Hopefully this will fix the problem....
I appreciate the help from everyone as I would not be this far in getting it fixed. Hope I can return the favor.
Baldie88, I sent you my e-mail address. This will be a big help. Thanks a lot.. Owe you one....
I will let everyone know what I come up with and hopefully this post will help everyone else so they do not make the same mistake as me!!!

 

[88kfb]

Just an update for the third brake light issue. It was indeed the switch. What messed me up was I was thinking that the switch was seperate from the actual third brake light. For information to anyone else who has this issue:

The main brake switch does contain both switches! The other physical switch is for the cruise control.

Thanks to Baldie88 for the schematic. It helped in my jumpering to verify that the third brake lights do indeed work.

Also thanks to Rob.. should listen to ones who know best!!!

Now I can go topless in my 88 without looking silly when I brake and the third brake light doesn't work...
Thanks to everyone....