dash lights

[george71]

Dash lights on my 71 f250 camper special wont come on. It has a relay part number c8tb13a435a that snaps when i pull the head light switch out. And clunks when i turn off. All other lights system work. Just the dash. Is this a relay problem? or circuit breaker attached to it the culprit? I read in this forum a guy was having a problem and was wondering if anybody had an idea? The dash light fuse is also good. What is the proper name of this relay cant find it in my ford book's? Thanks for your help.

george 71

[fordman]

the dahs lights are controlled by turning the headlight switch. inside of the headlight switch is a rheostat. that rheostat can turn the dome light on if turned all the way. it can also adjust the brightness of the dash lights. if the rheostat is bad. then a new switch is needed. if nothing happens when the knob is turned the rheostat or its contact is bad. and can't really be fixed. i tried once by replacing the rheostat from another ford switch and it still doesnt work smoothly. but it did fit. but new switches are about 10.00 for a china made switch.

[VirginiaCityFord]

There are many vendors that make good switches too, like LMC that are made from original Ford Design

[TNIceWolf]

Pull the headlight switch out to activate the exterior lights. Then turn the knob counterclockwise and see what happens. Then turn it clockwise and see what happens. That should give you an idea whether the switch rheostat is bad or not. If nothing happens either way I myself would first check the bulbs in the panel.......it wouldnt be all that odd for all of them to be burned out after 40 or so years. Always go the simplest route when troubleshooting. The basics rarely will let you down and they provide a solid base for the unusual faults to be diagnosed. Also keep an eye on your heater control,interior light or factory radio lights while doing this. If any or all respond it isnt the dimmer rheostat. Unfortunately they may have burned out bulbs as well and they wont be much help if you havn't checked them first.

[george71]

Thanks for all the response. When i turn the rheostat counter clockwise the dome lights come on. Turn it clockwise goes out like it should, but still no dash lights. But the rheostat sound's crusty in side, but turns. Will order one and replace.

George 71

[FORDification]

I think I'd take the instrument panel out and take a look at the back. Your panel has a circuit board on the back, and it's fairly common for these to start coming apart over the course of the truck's life. If the circuit path to the lights is broken, they won't work.



If the board looks good, you might try carefully cleaning the copper contacts with a pencil eraser. And of course, while the panel is out, it'll be easy to pop the bulbs out to make sure they're still good.

[FordEddie]

I am having a similar problem with the dash lights on my 72 F100. When I pull out my headlight switch and turn it counter-clockwise, I do get a dome light, but I must wiggle the switch back and forth to get dash lights, sometimes not successfully. Does this sound like a rheostat issue? Would it make more sense to replace the whole switch?
Also I have no lights on my heater controls or my gear selector located on the steering column. If the bulbs are burned out on them, are they difficult to replace?

[fordman]

the heater bulb is easy to replace. the column bulb would have to have the wheel removed to replace it. you probably do need a different headlight switch or a rheostat.

[newb70f250camper]

Had the same problem with my dash lights not working, found out that the fuse box was rusted and had to clean for a good connection.

[huskerrush]

My dash lights only worked at the very "dim" end of the rheostat spectrum, so to speak. So dim, it was unsafe to drive by. Also when I turned the knob, it felt crusty, just as George 71 described. Replace the switch with a new one, works perfectly now.