Help with Electrical. Im at the car now.

[1carlover]

I've posted many threads about this same problem but still a problem. My 67 rt dash lights work then don't work. This is just dash lights. Just removed the dash and with headlights on there is power to the orange wire at the wheel plug. When turning rheostat power goes out. If dash was plugged in it blows the fuse. So what could be causing the short ??

 

[PurpleBeeper]

Short in the rheostat?

 

[1carlover]

Short in the rheostat? Ive tried different switches with same result.

 

[PurpleBeeper]

Then it's a short in the dash circuit board itself

 

[1carlover]

Then it's a short in the dash circuit board itself

New circuit board and gauges sent out to check all circuitry. No shorts in dash

 

[1carlover]

New circuit board and gauges sent out to check all circuitry. No shorts in dash

Thanks for your input.

 

[topside]

I'll assume everything else is working OK ?
Most wiring issues are due to a bad ground, but the rheostats themselves are often the culprit; especially the thumbwheel type '68-up.
Pull the switch and look for corrosion on the rheostat. Should be able to test for output to the cluster lamps with some fiddling.

 

[dadsbee]

Remember that dash lights and tail lights are on the same fuse....

 

[1carlover]

I'll assume everything else is working OK ?
Most wiring issues are due to a bad ground, but the rheostats themselves are often the culprit; especially the thumbwheel type '68-up.
Pull the switch and look for corrosion on the rheostat. Should be able to test for output to the cluster lamps with some fiddling.

There wasn't any corrosion present in either new switch. There's power on both sides of the instrument fuse until rheostat is turned up.

 

[1carlover]

There wasn't any corrosion present in either new switch. There's power on both sides of the instrument fuse until rheostat is turned up. Then no power either side.

 

[1carlover]

Remember that dash lights and tail lights are on the same fuse....

All lights are working. Issue is with instrument fuse blows when rheostat is turned.

 

[1carlover]

Remember that dash lights and tail lights are on the same fuse....

Mines a 67 rt with pull type switch

 

[RemCharger]

Does the fuse filament blow, or does it overheat the end of the fuse.........

 

[1carlover]

Mines a 67 rt with pull type switch

I agree there is an intermittent ground short in an unknown switch or circuit that grounds the rheostat circuit when turned and blows the instrument fuse.

 

[1carlover]

Does the fuse filament blow, or does it overheat the end of the fuse.........

It blows the filament.

 

[RemCharger]

It blows the filament.

And I get a red x for asking?

 

[1carlover]

And I get a red x for asking?

And I get a red x for asking?

Thanks for your reply.

 

[devinism]

At this point you are going to have to eliminate things one by one. And no assuming allowed.
Unplug anything with an orange wire, try the rheostat, repeat. That would be radio, console illumination, etc. Even the 'new' dash circuit board. If nothing changes the problem may lie in the dash harness itself. At some point an orange wire is grounding. Didn't you mention LEDs? Unplugging the dash c-board should should remove them from the circuit (for testing on the car)