I have been chasing corroded electrical connections on my 69 Cutlass S. The headlight switch was intermittently shitty and needed replaced. I bought a cheapo online. When I turn the lights on the marker lamps come on but dim and brighten as I turn the dimmer on the switch...like the dome light would. WTF is that? Bad switch..wrong switch...bad karma ? I dont have a working dome light yet...its there, I just havent gotten round to cleaning it up for testing.
Also when I turn the key on the dash lights come on. No change when I pull the headlight switch on...they stay on. I took the switch out of the circuit and the dash lights still come on with the key on. Is that typical ?

H

 

You've got some kind of bad short circuit(s) going on in there somewhere.

Look at and follow the schematic in the Chassis Service Manual to figure out where your wires are crossed.
Could be hatchet work of a previous owner, or possibly a melty area in the wiring harness (due to hatchet work of a previous owner...).

- Eric

 

I found wires within the fusebox/ junction/ bulkhead chafed thru to each other when redoing a 1966 442 a while back. Would not have seen it if I hadn't pulled each and every wire up to inspect closely. You could try a used OEM working headlight switch and see if that helps, easy enough to do.

At least pull the connector off your HLS and see if that cures the "dash lites on anytime ign is on" issue.

 

We have found that some of the headlight switches differ from year to year, so the universal one may be wrong.

 

Thanks MDchanic...Thinking you were right on...However the previous owner did not hack the crap out of the electrical system as fa as I could tell. I have not found any splices, Scotch Locks(total **** in my opinion) hacks, cuts and so on like you would see in previously owned classic car. The cheapo headlight switch was the culprit. Replaced it with quality Echlin "NAPA" switch and BOOM...Fixed the dimmer/marker light issue. I bought a ignition switch(mounted on steering column)also but have not installed that. Hopefully that will fix the other issue...turn the ignition switch on and the dash light come on. No shorts so far....