headlight and ignition problem...

[Dhill]

Hi everyone,
The 68 shortbed I bought runs good, but might have some problems with the wiring, but I don't know and maybe someone else has seen this before. When I was checking all the lights last night, one of the lowbeams on the pax side didn't work, so I figured it had a burnt element. But when I turned on the high beams and revved the engine, both high beams quit working at the same time. I think I either blew them out with too much juice, or maybe a fuse? Also at the time the truck died, and wouldn't start until I played with the key a little bit, and then it turned over, but now I only have one low beam light working.

Any thoughts?

Thanx

[bluef250]

Electrical issues are the pits. Two thoughts. First the ignition switch probably is on the verge of dying from your comment about jiggling the key to start the truck. The switch attaches to the back of the key lock set. Get a switch and see how it looks before starting the work. You remove the switch from the lock set, cut the wires, and connect the new wires. Second, check to see if the headlight elements are good. Do the rest of the constant lights work, like the parking lights or running lights (not blinking or flashing ones)? Since the light switch gets power from the battery through the solenoid, if lights are not working, then the light switch may also be on the way out also. The headlight switch has an internal circuit breaker before all the other connections which gets tired and can fail. Before replacing the switch, check the headlight circuit particularly the ground. Check the ground for the headlights and work back to the switch to make sure everything is ok, the wires and plugs. If there is a wire shorting then the circuit breaker would also pop. Clean everything and check that you have power at each junction.

[willowbilly3]

It kind of sounds like the alternator may have gone full tilt boogey there. If an alternator is full fielded it will smoke any lights that are burning when you rev the engine. This will also happen if you are running it with the battery disconnected. There are still a buch of us getting advice from old shade tree mechanics that think disconnecting the battery cable on a running engine is how you test a charging system. Bad advice.
The first think to do is check all the grounds, this is where any electrical diagnosis should begin. Get a test light and trace the power paths, see where there is juice and where there isn't. It does sound like you may need a switch, not uncommon. I drove one 69 for years that I had to jiggle the switch a little after I cranked it or it would just die. I can't quite connect that with the headlight problem though.

[rjewkes]

My light Prob was in the harnessess that went into the lights.