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Driving my 67 corvette and it shut down four times within a couple miles. Last time it would not start and I had to get it towed; the lights and clock do not work but the horn works. I am getting 12.7 Volts to the battery, alternator and starter and the fuses test fine. I had a problem earlier with possibly a bad connection at the relay for the horn. Fixed that and the car was fine for a two hour drive then this happened.
12.7 at the battery is a dead battery. You need 14.1. Buy a new battery and have your charging system checked out
12.7 is a fully charged battery with engine off.
rjblj: Look under the master cylinder at the two bulkhead connectors. The inside one (closest to center of car) has a large red wire in it. Carefully disconnect the connector (the plastic can be brittle) and look at the contacts. I expect you'll see that both sides of the pins are corroded. Clean them up and reconnect. It's also possible that the side that goes into the firewall has a pin pushed partially back into the connector. They all should be the same length.
Going from memory, the red wire should go to the bottom one I put the arrow on (EDIT: Its the top left wire). The wire is a larger diameter than the other wires in the group and it feeds all the voltage into the cabin. The horn relay is powered under the hood and is not affected by this wire. This one is really bad, yours may not be that obvious.
Last edited by 65GGvert; Jun 22, 2018 at 05:13 AM.
And DISCONNECT the battery before you start cleaning down inside that plug, it has battery voltage on it all the time. You can short it to other pins in the plugl
Years and years ago,35+, I had similar problem with my 67. I don't remember about the horn working , but ended up being a loose main wire connector on the horn relay. Another problem I had was loose main ground cable. good luck.
7-8 yeares back I also had something similar happen with my 67. start right up, ride for an hour or so, stop for a while. Get back in it and nothing....no power to anything. Got ti back home, traced the problem to the ignition switch. Changed it out with a new one, never had another problem. So check your ignition switch, about $25. replace if it is old or orginal.
Going from memory, the red wire should go to the bottom one I put the arrow on. The wire is a larger diameter than the other wires in the group and it feeds all the voltage into the cabin. The horn relay is powered under the hood and is not affected by this wire. This one is really bad, yours may not be that obvious.
7-8 yeares back I also had something similar happen with my 67. start right up, ride for an hour or so, stop for a while. Get back in it and nothing....no power to anything. Got ti back home, traced the problem to the ignition switch. Changed it out with a new one, never had another problem. So check your ignition switch, about $25. replace if it is old or orginal.
Max
Voltage to the clock doesn't go through ignition, so since the clock doesn't work when this happens, we're back to the main red wire feed from the horn relay through the bulkhead to the fuse box, which then goes to the ignition. That red wire is the only thing that matches the description of "horn still works, but no voltage inside cabin".
67 Corvette electrical problem
