I recently bought a 1989 F-250 4x4 fixer upper.

When I bought it the dash lights didn't work and now I'm running out of places to look next. What I have right now only effects the dash lights. ALL other lights work perfectly.

So, far I've replaced the headlight switch as it was burned up. Once replaced the fuse is now blowing. I started pulling things apart looking for the short and didn't find anything so far. I've removed the gauge cluster and checked all the lights and circuits, which are good.

Next I removed the radio and found a cluster of a mess behind it. I figure my problem is hidden in that mess of wires. Some have been cut and left hanging, others have been spliced to the radio.

Also, are there lights that can cause problems inside the air/fan control module above the radio? (that is also stuck in defrost, but that will be another issue for another day)

What I've been looking for is a diagram or wire color codes for the dash lights that go into the radio. If I can find that wire, which is most likely one of those hanging loose and complete the circuit, I hope to get my dash light back.

All my searches here have come up with nothing. Does anyone have the colors codes or schematics for the dash lights?

 

I'm assuming Fuse #17 is the one blowing.

It provides 12 volts on a Light Blue/Red wire for illumination of the Instrument cluster, Ash Tray, HVAC controls, Radio and Windshield wiper/washer switch.

 

If the truck is wired for a trailer hitch, check that wiring too.

Got an aftermarket radio? Maybe the OEM radio wiring is back there touching something it shouldn't. '

Now you know what fried your switch.

 

Actually it is fuse #10 (5amp) that is blowing, though not all the time now. (#17 is for the Anti-lock brakes.) After looking behind the radio I found the blue/red stripe wire and it is connected to the back of the radio. While there I checked for any shorts and didn't find anything. Though I think the short is back there someplace. As the fuse never blew while the radio was out.

Correct that the radio is after market. I heard it was recently replaced, which would lead me to believe I'm fighting a shoddy install. As far as I can tell this radio doesn't have dimmed lighting, so there is no need for the blue/red wire to be connected. As for the OEM connector? Yeah, about that. It was cut off and all new splices were installed. *face palm*

While I'm in there, should I also be looking for any fusible links that deal with only the instrument lighting?

Oh, on a final note, the trailer lights also work fine.

 

Found it!

Notice the light blue/red stripe dash light wire spliced to the radio's black ground? Yeah... one shoddy radio install now fixed. Let's just hope this guy didn't do any other electrical work!

 

Did you find a good place to connect the radio ground? It might play better, now.

Amazing how some installers don't even try to do it right.

 

Yeah I did. I simply capped the unused light blue/red wire and connected the ground to an actual black ground wire that just so happened to be there. ;-)