Hi all,

My mostly restored 1980 (remaining items included any and all wiring harnesses of course) stopped starting recently - no starter noise when I turn the key to "start". I've traced the problem to the wiring for the switched +12V to the solenoid (the S terminal is not receiving +12V when I turn the key to "start"), somewhere between the solenoid and the fuse box. I've pulled/checked all fuses, all are good. When I turn the key to "start" the red light on the gauge cluster turns a brighter red, so I presume that all inside the passenger compartment is ok.

I traced the purple switched 12V solenoid (S terminal) wire to a junction box underneath the power brake vacuum booster, and things look pretty nasty down there to where I can't see if that junction box connection on the engine side can actually be removed or not? Anyone happen to know the answer to that? I don't see in pics of the 1980 engine wiring harnesses (on Eckler's and Lectric Limited) a connector that size so I'm scratching my head on this a bit.

Also I have an MSD Street Fire CDI Ignition that requires a switched 12V source and that source isn't hot for 12V with the key turned to start either. It's connected to a different wire that comes out of the same wireloom that the purple solenoid wire belongs to. That wire is so old I can't tell the original color, could have been a yellow or perhaps it was white and has yellowed.

And I have looked at a new engine wiring harness, they run ~$240 and of course the problem may be on the other side of that junction box. Just wonder if anyone's run into this?

With the weather starting to get nicer I'm wondering if the sweat of taking it to a shop, being charged at electrical rates, not knowing what the final bill will be, might just be worth it vs. the amount of time it might take myself to solve this problem when I've only got weekends and a few hours after work on a couple of nights per week, to work on it.

Also while I'm at it I have the GM Shop Manual schematic and it pretty much bites, has symbols and refers to wiring in ways such as "5.0 Ppl" with no legend to explain things. I saw in a previous post that Doc Rebuild has wiring diagrams with pics showing where things are connected, for up to 1973s. Does any one know of such wiring diagrams for 1980 and other years?

Many many MANY thanks in advance for any insight that is provided!

Cheers!

Steve in Seattle

 

There's a thread on the Forum here advertizing wiring diagrams for C3s. The 80 assembly instruction manual (AIM) shows the installation of the engine harness and all of the various connectors.

 

I guess I have a different assembly manual then - I purchased it in 2000 or 2001 from Helm Inc, the title is "1980 Corvette Assembly Manual" and it contains no wiring diagrams period.

And... I should have mentioned it is an automatic trans so... I DID find a decent wiring diagram in my Chilton's manual of all places (not in my AIM or Shop Manual or the schematic that accompanies the Shop Man, nor in my Restoration Guide) and it has a nice breakdown of what applies from the Start pin of the ignition to the solenoid for manual vs. automatic and the automatic trans DOES have a backup-light switch in the circuit.

When I saw that and saw a pic of that backup-light switch I recalled seeing that very switch behind the passenger seat under the tray.

So next question - does anyone know of a way to test the backup-light switch and/or bypass it?