Low beams only work when I put on high beams. Clamshells work fine. I might buy a light switch but I'm not sure. Any suggestions where I should start troubleshooting?
I am not much of a mechanic, but as an electronics tech I would look for something common, such as the dimmer switch on the floor. They have a hard life as people stomp on them. I don't know enough about the pin arrangements, but you should have contact on a set of contacts on low beam and two sets on high beam. If that checks out my next step would be the light switch. I am dubious on this though because it has much less wear and tear than the floor dimmer and doesn't control the change between high and low beam.. After that, I would chase grounds. Sorry I couldn't be more specific, but, as I said, geek, not a car guy (yet).
Mine did something similar and I cleaned up the harness connectors for the headlights. Also scrubbed down the headlight pins.
Sounds like the floor switch. When in low beam mode if lights don’t come on try depressing the switch repeatedly without depressing hard enough to go into high beam mode. If your lights come on momentarily while doing that then it’s the floor switch. Good luck
Are the low beam filaments intact and working? I would bench test the headlights before you start potentially chasing your tail
The low beam bulbs have 2 filaments . One is for low beam and the other is for when the high beams are used . So on low beams only the low beams light but when you put them on high beams ALL 4 headlights light Either the Dimmer switch is bad OR the Low beam filaments in the low beams are burned out .
I ordered a new floor switch and changed it. When I attached the plug into the new switch the switch just fell apart. Piece of junk. I ordered another switch but low beams still will not come on without the high beams. I did not know low beam bulbs have 2 filaments. That will be my next step.
I had the same problem and it ended up being the floor switch. Changed it out for another 50 year old unit and all is well. I realized I had this problem when I was going to the Photo Shoot for the 69 car. Ended up driving 28 miles @ 4:30 in the morning with high beams on. I am sure there were a bunch of guys cursing me out. Duane
Twenty years ago I needed a dimmer switch for a ‘78 Cadillac. The warehouse where I worked stocked Delco and Borg Warner. I printed a ticket for a Delco and when it came down the belt I opened it and it had BUB-Made in China on it. Pulled the BW, same switch, same sticker. I bought the cheaper priced one and it soon failed. Next week I hit PullAPart and harvested several ‘real’ GM switches. Never had trouble with them. Patrick Duane, if your headlights are like my T-3s, the people in the zillion candlepower trucks, HID lit modern cars and even new Toyotas don’t even notice them, much less get blinded by them.
Patrick, The "T-3's I bought were the reproduction Halogens. (Got them from Todd.) They knew I was there. I had the same problem with a new ignition switch, it burned up inside. Replaced it with a used unit and it is still in the car 20 years later. Duane
Good to know the repro T-3s are brighter; when I run out of used originals I’ll probably buy a set. Patrick
I have had the Lectric Ltd. Repro T-3's at least 15 years. They are plenty adequate for driving in NYC. They might not be as good for rural driving.
Maybe 20 years ago we drove to Savannah from Fort Lauderdale with a friend in her new Suburban (Expedition?). On the return trip we left late Sunday, and as soon as it got dark the low beams went out. Drove through the night with high beams only. People would honk, swerve. block us, get behind us with brights, you name it. Can't say that I blame them. Most impressive was a trucker with some gawdawful bright light hecshined backwards at us as we tried to pass. Glad to get clear of him.
High Beam switch . . . . $17.00 - In Stock at www.Stage1Restoration.com You could check your Tan & Green Wires at the plug also (Just to make sure your existing switch and wiring is working) IF so, then replace the bulbs!! These are made by Lectric Limited . . . .
Sounds like the dimmer switch. Unplug it and make a jumper out of a short piece of wire and a couple of male terminals. jump from the hot lead on the plug to each of the other terminals and see if high and low beams work. If they do then replace the switch.
If you attempt this make sure you have the headlight switch knob pulled out or there will be no power at the dimmer switch
Had this problem on my 62 special 4 headlight setup, found wiring on the driver side lamps needed rehiring
