Odd Original Light Switch Malfunction

[ericr]

has anyone had this issue: the lighting switch has the correct détentes at the steering wheel, yet, every position (except the off position) turns on only both the high/low beams in each headlight. I unplugged one of the headlamp conduits and tested each one of the three contacts with a test light and each is indeed always hot, no matter where the switch is at the steering wheel. The only position working correctly is the off position.

late '29 roadster with two-lamp headlights, and 2-tooth column

[redmodelt]

If the switch has the spade type connections, could someone have done some creative miss wiring and has the wires in the wrong places.

[Ron in Quincy]

If you installed new headlight wiring harnesses, some of those available have large connectors and will short across bringing on both high and low beams. If this is not the problem then check the terminal block in the light switch to be sure it is terminated properly. Generally the wires to the headlights are: Red with tracer= high beam, Green with tracer= low beam, Yellow with tracer= Parking light.

Ron

[Mike V. Florida]

Reproduction parts often does weird stuff.

[ericr]

Originally Posted by Ron in Quincy

If you installed new headlight wiring harnesses, some of those available have large connectors and will short across bringing on both high and low beams. If this is not the problem then check the terminal block in the light switch to be sure it is terminated properly. Generally the wires to the headlights are: Red with tracer= high beam, Green with tracer= low beam, Yellow with tracer= Parking light.

Ron

well, actually, this is indeed a new wiring harness from Bratton's...

[Brentwood Bob]

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Can still be miswired.
Bob

[Tom Wesenberg]

I've seen the same thing and it was caused by the headlamp contacts touching each other. Had to use a Dremel to grind the diameter a bit smaller.

[KGBnut]

I agree. Sounds like reproduction headlight bulb sockets. I was never able to get those to work. I ultimately restored a set of original sockets and have never had a problem since.

[ericr]

thanks, one and all, for your helpful replies, I'll check them all out!

[ericr]

well, you guys were right....the repro socket tips in one headlight were touching each other and enabling the current to flow backwards through the switch into the other headlight, lighting every bulb in it. thanks again.

[Brentwood Bob]

What was the fix? Replacing the bullet ends with others?

[ericr]

Originally Posted by Brentwood Bob

What was the fix? Replacing the bullet ends with others?

I already had the Bratton-style blunt ends on the main harness. BTW I perceived that to be a problem with former harnesses back in the 1970s and I cut off the incorrect ends back then and substituted small bits of copper tubing with the wires soldered into the tubes.

I am waffling on what to do with the headlight sockets. I seem to read conflicting information on whether Walt's sockets are workably better than other vendors'. People here say they work fine, his catalog describes them as "fair" quality.

One thing that deters me from going to modern connectors is that apparently some repro sockets have high/low wires reversed, and combine that with the repro bulbs being confusing as to which filament is top/bottom.

[Brentwood Bob]

thanks for the update.
no words of wisdom, I have changed out a harness that was incorrectly connected to the switch plate. Also had to solder on different ends to get the lights to work. PITA. Now I am trying to get a good harness and switch lined up for the ccpu.
Bob

[Fud91]

Gents,

Wanted to throw my 2 cents in here as well. I had the same problem over the past week and thought I had "bad" repro sockets. In the end, the volt/ohm meter showed the way and I had a bad ground in my left headlamp. Unbolted it from the cross bar, wire brushed all the rust away from the "ball socket" that the headlamp bolt sits in. Put it back together and bingo! My problems FINALLY disappeared! As has been said before, the last place you think to look, is where your problem most likely resides. Thanks for all the posts here - they kept me on track!

Fud