73 Mustang convertible

[Bronx]

I just bought a 73 Convertible and I have no dash lights and gas gauge doesn't work. I checked all the bulbs and fuses and all look good. I'm guessing the switch is good as the headlights work,and when I turn the knob the cabin lights work. Any other suggestions or help would be greatly appreciated.Thanks

 

[Fast68back]

Stupid question, when you turn the knob and the cabin lights come on, are you turning it fully in the opposite direction or stopping just after the click to turn the cabin lights off?

 

[Midlife]

The rheostat on the headlight switch controls the dash lights. It could be bad and the rest of the switch be fine.

To check the function of the gas gauge, remove the wire from the sending unit and briefly ground the wire while the key is in the ACC position. The gauge should peg high. If not, the wiring or the gauge is bad; if it does peg, the sending unit is bad.

 

[Bronx]

well after testing the sending unit,I'm guessing it's the gauge itself. I have had the dash apart twice,wiring all looks good,and bulbs are good, One question tho, since the tach & gas gauge don't work,and no dash lights,yet the speedometer works,(no lights tho) could the circuit tape be bad? If not I guess that just leaves the reostsat on the switch at least for the lights. uugggg I hate wiring troubles....LOL
Oh, and if anyone knows where I can find some of these parts I'd be grateful. Checked alot of places online,but no luck with switch,or gauges

 

[Midlife]

The tach isn't driven from the circuit card but directly from a plug. And yes, the circuit card can be bad. Do you have dash lamps on the 3 gauge cluster? If so, then the problem is isolated to the dash cluster itself.

The speedometer is mechanical and completely independent from any wiring issues.

 

[Bronx]

No dash lights, all the bulbs check out, so I'm thinking its the reostat.