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desmomini · Joined: 06 Aug 2017 Posts: 7 Location: South Carolina

Somehow I blew out all my dash lights.

Odometer, speedometer, clock, this pressure, that pressure, what have you.

All fuses appear okay.

This is a 1978. From what I see, there is no single fuse or relay that controls all the interior dash lighting??

Please give me a simple solution, and I promise not to be stupid again.

brian19600 · Joined: 28 Oct 2013 Posts: 375 Location: NJ/CT

Rheostat dirty?
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78 924

Kenodog · Joined: 25 Jun 2003 Posts: 2651 Location: Vancouver,B.C.

It is very common for the light switches to fry out. I have seen many that were so cooked I was amazed the car hadn't caught on fire.

Leigh
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1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140

desmomini · Joined: 06 Aug 2017 Posts: 7 Location: South Carolina

Figured it out!

Tucked in the wiring behind the lightswitch, there is an (undocumented) in-line fuse that bridges the blue/white wire that feeds the potentiometer
wheel. Sure enough, once I figured how to open the case (hint: pry first, then turn) I found a burnt out 8 amp bullet fuse inside. Replaced it, and my dash lights are back. Well, except for the speedometer light, which I'll replace when I get the whole unit out to fix the odometer.

While the light switch was out, I sprayed the whole thing with electronic contact cleaner. Those 1.2 amps bulbs are really shining now!

The irritating thing is that this in-line fuse is not mentioned in the owner's manual, the Haynes manual, or anywhere I could find on the web...until now!