Dimmer switch circuit trouble

[Bob H.]

I installed a repro headlight switch and the dimmers worked perfectly for a short while. I figured the rheostat went bad so I now have an NOS replacement which did not solve the problem. I don't know what I am missing

If you put 12 volts to the fuse you get the lights. So that tells me I'm good from the fuse to the lights. On the other side of the fuse is the green wire which checks good continuity right to the green terminal of the switch I have my 12v on the red. Checking the switch on the bench, I see the resistance between the green pin 2 and 3 as I turn the rheostat. Shouldn't there be 12 volts between the pin 1 (red 12v) and one side of the rheostat? I don't know the internal workings of the switch. It keeps looking to me to be the switch

I read no voltage on the green lead regardless of where the rheostat is

[Richard M.]

Re: Dimmer switch circuit trouble

Bob what year and what is the HL switch part #? (edit, apparently for the '72 as I just saw your recent thread)

The feed for the dash lamps comes from the Park or HL internal switch circuit when on, through the rheostat then to the fuse panel, to the lamps.

When you check for voltages at the panel, ensure you're touching the fuse "clip" itself. Quite often there's a bad connection between the clip and the fuse which can lead to misleading results.

You may want to remove the fuse and clean the clip with a wire brush or abrasive that'll fit in there. Keep HL power off and/or disconnect battery first to be safe.

Rich

[Bob H.]

Re: Dimmer switch circuit trouble

1995191 d1542