Apathy

Ok, so my light switch has burned out again... Its my second time changing it and the wiring harness for the lights... What should I look for to avoid this? thanks...

Carzy Driver

I think I read about this on another forum, but adding a inline fuse on the main power wire is supposed to keep from frying the harness and/or switches. I'm unsure about the amp fuse to use but they are fairly cheap so some trial and error starting with lower amp fuses shouldn't hurt the wallet that much.

Icemark

As covered in the archive, and countless threads here; there are a couple reasons why the light switch fails.

Issue #1 too much resistance in the bulbs sockets. The bulbs get replaced or the old dialelectric dries out and seals fail allowing moisture into the socket. The corrosion that then happens increases the resistance to the point of overheating the weakest point. Usually the light swith harness were it meet the light switch. Because the amperage load never exceeds the fuse value (until the wires melt enough to touch) the fuse never blows. (of course adding a fuse as Carzy driver suggests also does not solve this- there is already a fuse at the fuse box less than 2 feet away- so an extra fuse is a waste of time and money).

Issue #2 internal solder joint failing on the switch. Yep, headlight switches get the same cold solder joints as any other circuit board found in a 15-20 year old car. This failure is generally only the dash lights, but occasionally will be also the parking light output wire of the switch.

How to fix???

For #1 clean the bulb sockets on all the parking lights, use some conditive grease on all the contacts for the bulbs, and use the relay set up as described in the 2nd gen archive here.

For #2 get a rebuilt or new light switch. If you try to partially rebuild it yourself, you'll want to replace the solder joints where the pins meet the circuit board.

The absolute last thing you want to do is just plug in a junkyard replacement switch without re-soldering the pins at the circuit board (and you need to remove the old solder, not just heat it up... just heating it up results in covering up the failing joint- sort of like filling a crack in the cement in your driveway. Filling it will only temp fix it, but pouring a new driveway will solve the problem all together.)

New switches of course won't have that issue.

And I do sell several types of rebuilt FC headlight switches as well as a pre-wired relay for adding the protection (as covered in the archive thread).

rotary racer 666

i hd this problem too...if you have a deck, check the wiring, i took my deck out, and it didnt burn out anymore, it has something to do with the ground or something, in my car, if my deck was on, and i turned on my headlights, my deck would turn off, so try taking your deck out, if you have one, and re wiring it

Icemark

well it is common if mickey mouse wired an aftermarket stereo, for the installer to hook up the illumination wire (Red/Black) as a ground. This of course would blow out the fuse, rather than the switch though if the radio was otherwise grounded. If the radio was also improperly grounded and the antenna was also not grounded then you could in therory let the genie out of the switch (smoke/burn up the switch)

But a proper install on an aftermarket radio will of course not have that problem.

Only if micky mouse installed the radio would that happen.