tj90

In the process of replacing the headlight motor boot and when plugging everything back together, I saw smoke coming from the plug wires right at the headlight motor. I quickly unplugged it but the damage was done. The red and green wire melted its insulation and the headlight switch at the dash is frozen (it no longer is 3 position).

I am still trying to figure out what happened. Im not getting 12V over the red and green wire anymore. Fuses look good. Im guessing the wires fused somewhere else. Maybe I got the plug polarity wrong?

Any ideas where to start? Im thinking of removing the dash and inspecting the switch first.

Im worried that the wiring harness is trashed in the car.

odonnell

You don't need to pull the dash to remove that switch. Just pop it out by reaching under the dash, and depress the 2 tabs (top and bottom IIRC) and slide it backward.

tj90

Thanks for the tip. I pulled the switch and the red and green wire insulation looks cooked by the switch. Its part of a very large harness a few inches from the dash switch. There is no way for me to inspect the wire unless I start cutting and digging. Still trying to figure out what happened.

snb13

Those switches are a known issue in the early cars. If you don't know the history of the car it's a good idea to replace it. You're lucky you were there to catch it before it started a dash fire.

tj90

Thanks for the tips. I ordered a new switch. The one that was installed is now frozen in the off position.

I was thinking about what happened and it may have been some wd40 I used to lubricate the new boot when slipping over the end connector. Maybe the oil caused a short?

I checked the red and green wire for continuity. Its still intact from the motor to the switch. I also checked the wire to ground and other adjacent wires - didnt detect any shorts to ground. I ran the probe over the cooked insulation and could not detect a short. I may have dodged a big bullet.

marc abrams

Ether your motor is shorted or you forced the plug on the motor backwards. I would proceed with caution with the new switch, because that circuit is NOT protect by a fuse! Note, WD-40 doesn't cause short's and is a great way to protect against corrosion.

tj90

Marc: Thanks for the information. Reverse polarity is a possibility. Despite the chamfered corners, the plug can be reversed. I was not careful enough to be 100% sure my polarity was correct. Ill replace the switch and see if the voltages are correct before plugging in. Thanks!