Dash light dimmer switch failure?

Posted By: 68Bullet

Dash light dimmer switch failure? - 01/22/07 06:43 AM

I just got my 68 Coronet back on the road and realized I never tackled a problem that occured this summer: I have no dash lights. I traced the problem to the dimmer switch. The main light switch sends power to the dimmer switch, but I have no power from the dimmer switch at the instr light fuse. Is the dimmer going bad a common thing? Or is there something I could be overlooking. If it helps, the console/dome lights work, but the dimmer doesn't dim them (although I dunno if it's supposed to).

Posted By: JohnRR

Re: Dash light dimmer switch failure? - 01/22/07 12:49 PM

yes the dimmer going bad is common , good used or NO$ is the only options , the resistor wire coil opens eventually .

best way to confirm is to put it to the full bright position with the lights on , if you get lights its the switch .

you confirmed the guage assembly is grounded well ?

Posted By: 68Bullet

Re: Dash light dimmer switch failure? - 01/22/07 05:13 PM

hmmm, no matter where i rotate the dimmer switch i get no instrument lights. i was thinking of jumping the connector to 'bypass' the dimmer. As a test or otherwise. Bad idea?

Posted By: dbdartman

Re: Dash light dimmer switch failure? - 01/22/07 05:56 PM

Quote:

i was thinking of jumping the connector to 'bypass' the dimmer. As a test or otherwise. Bad idea?

Good idea & likely the most common "low buck" fix there is. This won't hurt a thing.

Posted By: Sinitro

Re: Dash light dimmer switch failure? - 01/22/07 08:10 PM

The rheostadt (variable resistor) is dirty or broken in continuity.. Pull off the 3 terminal connector and jumper the 2 orange wires using a short wire lead with male tab 0.25" terminals. Now you will get the full 12V to the dash lites. The other terminal is for the Dome lite, and you should run a short lead back the switch for this.
For the Dome lite circuit to work rite the dash ground circuit must be tite and secure.

Note that for the dash lites the only question about grounding is the bulb socket itself on the circuit board. Make sure the circuit board has a good solid ground, as there is no grounding through the dimmer switch for the dash lites. Its purpose is to reduce the 12V down to 5V and this is done on the 12V+ side which is above ground..

The single wire is for the Dome lite circuit.

Hope that helps...

Posted By: mickm

Re: Dash light dimmer switch failure? - 01/22/07 11:45 PM

guy named rich sells these, i think he rebuilds them. i'm looking for one for my 70 RR. he has one but says it has a little bubbling on the chrome, probably not noticable when installed. i'm waiting for a better one. he contacted me here on the board after i posted a similar question. his email is runnernest@yahoo.com.

mickm