sheltonoil

I only have low beams. No high beams from any of the 4 lights when switching with the foot dimmer. Tested the green wire coming from the foot dimmer, it has power there. Tested it again at the high beam lights, no power. It seems odd the green wire could short out b/w the switch and the headlamp but not the tan (low beam) wire, since they're bundled together all the way to the lights (right?). I'm hoping someone has some ideas I can try before I have to start tracing that wire and maybe cutting open the bundle to try to find it.

TripDeuces

Could be a bad high beam switch, they do break.

oldcutlass

It is not a short, its an open circuit. Jumper the blue wire from the dimmer switch to the green wire, check voltage at the light socket. If none then check the bulkhead connector under the master cylinder, that is the only break in the circuit between the dimmer and the head lights.

sheltonoil

Thanks. For my electricity education, if I've already tested the green wire coming out of the foot switch with a test light and it had current, what could cause the result to be different running a jumper b/w the blue and the green?

oldcutlass

Because if there is even the slightest connection you will get voltage there with no load. If you jumper the connector you bypass the switch.

sheltonoil

Ah, thanks. Guess I'll try to do that tonight as well.

sheltonoil

Ran jumper bw blue and green wires at the dimmer switch, power to green obviously but still no power at lamp. Appears to be a newish dimmer switch btw - not the original, at any rate. I took a peek at the connector under the master cylinder, and it's not exactly convenient to get to. It's so filthy I couldn't really tell how to remove it, but I gave it a couple of tugs just to see. It didn't come loose and I didn't want to mess anything up, particularly if there were other things I should check first. If that IS the next step, how do I remove it?

oldcutlass

There is a screw in the center of the connector. Since you jumpered the dimmer switch connector switch and still have the same issue then you need to move forward. Follow the green wire look for a bad connection (open circuit).

sheltonoil

All right, I won't bug you for a while on this one. will follow up once I have a chance to finish tracing this down. Thanks.

oldcutlass

I'll be out of pocket until later this afternoon. You have enough to go on, you ruled out almost everything behind the bulkhead since your low beams work and jumpering the plug for the high beams did nothing. Like I said its from the switch plug forward so the next logical place to check is the bulkhead connector. If you have voltage there then check where the green wire connects to the high beam jumpers for the other 3 lamps.

svnt442

There is always the possibility that all 4 hi beams are blown, albeit a slim one.

joe_padavano

If it's an old car, not that slim. But again, if you test the headlight connectors and do not get power on the high beam terminals, obviously the problem is the wire. The high beam wire daisy chains from the LH low beam connector. That crimp is the single point failure in the whole system. Extract that terminal from the connector body and check there.

oldcutlass

Did you ever figure this out?

sheltonoil

Haven't had a chance to do it yet, bc of more pressing issues and limited time. But it's not too far down the list. I'll follow up once I get to it.

MDchanic

Note that the screw in the center of the bulkhead connector has a ⅜" hex head.

You won't get far with a screwdriver.

Good luck!

- Eric

sheltonoil

Thanks - that's good info to have. Got to clean off a layer of crud to even get to it first...