[jshinbot]

I fixed my ARC vie the Gubi method this weekend. Admittedly, mine wasn't in terrible shape. It would Christmas tree when cold, but would usually settle down after a minute. Now it's solid all the time! I might even miss the dance sometimes.

I was hoping fixing this would return my instrument lighting and clock, but it did not. The clock checked out on the bench and all the bulbs appear to be in good shape when inspecting them. Fuse 14 and 15 are good (replaced today, just to be sure). Dash, ARC, clock, and all dash-adjacent buttons do NOT light up under any circumstances. I have never seen these work since I've had the car. The clock used to sporadically kick the backlight on after several miles into a trip and then cut off with the ignition, but it does not do that anymore.

The interior lights DO work as intended. Strange.

I THINK the next step is to remove the ARC board from under the panel above the glove box and see what I can see there. Anything in particular I should be looking for?

 

[Gubi]

Could be a bad rheostat. Try moving it back and forth a bit, see if that helps. If that doesn't work, pull it out and disconnect it. There are three wires in the connector, jumper between the two that aren't black. If that makes the lights work your rheostat is bad.

 

[jshinbot]

Could be a bad rheostat. Try moving it back and forth a bit, see if that helps. If that doesn't work, pull it out and disconnect it. There are three wires in the connector, jumper between the two that aren't black. If that makes the lights work your rheostat is bad.

Are the dash lights supposed to be on with ignition? Or do the headlights need to be on?

Thanks for the recommendation. Will try that this week.

 

[Gubi]

The headlights need to be on

 

[jshinbot]

Ok! Dimmer was certainly part of the issue. I applied some contact cleaner and rolled it end to end a few times.

This brought back ARC backlights, "cigar" lighter and ash tray (according to manual ) lights, and the backlights on the buttons surrounding the dash. They all dim appropriately as well!

What still isn't working:
Dash cluster has no backlighting. I replaced this in the last few months, so it's possible I did something wrong on assembly, although ALL other functions work flawlessly. It seem unlikely that every bulb is bad, but I suppose it IS possible.

Clock has no voltage whatsoever. No backlight, no time. Again, both tested good on a bench yesterday.

 

[jshinbot]

Looking at the factory manual, it looks like I was mistaken. I thought the clock power circuit was behind the rheostat, but it looks like I'm wrong.

C7 = clock
N16 = Tacymetric control unit (does my car have this?)
N19 = performance gauge control (I'm pretty sure my car does NOT have this)

It does appear that the clock circuit is isolated. It also appears it draws all connections through G111 ("connector for dashboard instruments wiring"). Is this located in the fuse box access? Seems like a good place to start (along with the fusebox grounds, which I also assume are in there).

I THINK I've got a handle on what these wires to the connector do, but please help me out:

SB (Pink/White) = switch +12v
N (Black) = ground
G (Yellow) = ?
RN = Red/Black = constant +12v