1966 Headlight switch burning up interior lights staying on

Ford guy
Last seen
Joined
Oct 6, 2018
Thunderbird Year
1966
I have an issue with constant voltage going to my interior lights and my door lights when I plug the headlight switch in it appears to get so hot but it’s burning, I have DC coming to the switch from two different wires, a block and a yellow and a green with the red stripe should I have voltage at both of those when I have the switch hooked up and try to turn the dimmer switch or turn the lights off you can see power is cut but power still there I Donely dim the light they stay on I’m at a loss,I restored the car from front to back still working on the wiring issue though any ideas
 
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I have an issue with constant voltage going to my interior lights and my door lights when I plug the headlight switch in it appears to get so hot but it’s burning, I have DC coming to the switch from two different wires, a block and a yellow and a green with the red stripe should I have voltage at both of those when I have the switch hooked up and try to turn the dimmer switch or turn the lights off you can see power is cut but power still there I Donely dim the light they stay on I’m at a loss,I restored the car from front to back still working on the wiring issue though any ideas

You most likely replaced your standard headlights recently with higher intensity ones. The original headlight switch will not take the power increase & therefore gets hot & can burn out the switch. Many decades ago, when the increase in lumens for headlights increased, the original switch could accept the minimally higher voltage, until you turned on your high- beams & all four headlights on, it would then eventually push too much voltage thru the headlight switch, causing the headlight switch built in circuit to disconnect. If if you turned off the high beams, the circuit would eventually reconnect. If you put replacement higher output headlights in more recently, your headlight switch may have been permanently damaged. Since the circuit that turns on the interior lights ( by twisting the headlight switch knob until it clicks), even though it's not that part of the switch may now be allowing the current to flow through to the interior light circuit & draining your battery. I'm guessing that either your dash lights do not work either or they will not dim, since that part of the headlight switch was also affected. When I had that problem, rather than replacing the original switch with the same style, I checked out some later Ford products that had more modern lights (something in the late 70s or early 80's) that had the same wiring harness plug as my T-Bird switch & then used it as a replacement. I think there was some difference between the shaft lengths and I either had to remove the original shaft or possibly just the knob so once in place, it looked original protruding from the dash board. Since that time, suppliers many have created a suitable updated switch assembly, and save you the reconfiguration that I went thru. Some of my friends, who knew of this problem, just replaced their headlights with stock type ones.
 
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