77 headlight switch
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7th Gear
Joined: Aug 2015
Posts: 7
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77 headlight switch problems
Have gremlins in my electrical system. It seems when I turn my key to accessory or go to start car side marker, tail lights, and front parking lights come on even with headlight switch in off position. Weird thing is that I can turn headlight dimmer switch counter clockwise and they all dim except the dash and gauge lights stay bright. With key and ignition to off postion headlight switch works normal and dims dash lights. Its only when ignition switch is on thatheadlight switch acts funny. any ideas im stumped.
Last edited by Rich Trevains; Aug 2, 2015 at 08:54 AM.
Pro
Joined: Jul 2014
Posts: 566
Likes: 64
From: Sebastian,FL
I had a issue with my h/l switch also. My guess is that after nearly 40 years the potentiometer was just flat worn out. Mine worked fine until turning on the lights, then I would also have my left t/s indicator illuminated. Turn signals still worked fine, just weird illumination. If I adjusted the switch I could cure it for a few brief seconds. I replaced the switch and cured all the odd issues, and yeas after removing the switch I could see the old coil covered with dust, grime and unknown residue
8th Gear
Joined: Jul 2015
Posts: 8
Likes: 0
When ever I diagnosed "odd" electrical problems you always start with all the major grounds. If a large ground is lost the components will seek ground where ever it can. This causes these odd/interesting complaints. Try to find an electrical schematic but start with the large grounds first i.e. big black cables, battery/engine block etc.. and keep moving. I will also add even through a ground may "look" good, I would recommend that you still remove it and clean it.
If all the grounds check out you have to get a good copy of the electrical diagram for your car and start tracing circuits with a volt meter and find out where the problem is. Be very careful of past bubba installs of radio's/fog lights or what ever.
If all the grounds check out you have to get a good copy of the electrical diagram for your car and start tracing circuits with a volt meter and find out where the problem is. Be very careful of past bubba installs of radio's/fog lights or what ever.
