Problem with climate lights/light control box/dimmer switch

[mechanicalmoron]

At one point (and a few more besides, since it's repair) my radio light control wire touched ground, and, as they are known to do, blew my light control box (little white box under the kick panel, by the fusebox) before the fuse blew.

So, I got my dad to solder a jumper around the burnt trace (me being a solder disaster) and my cluster lights worked again.... woo.

But, my climate lights, (and I think backlights on stuff like cruise, I need to check though) still don't work. The little green led indicators work, but not the backlights -- same with the cruise/defroster buttons, I think: indicator works, emblem doesn't normally light though.

AND my dimmer doesn't work, my cluster is always at 100%.

I have checked the box again, and couldn't find any more damage, and I know the fuse works, because I had an accident installing my sterio, and it blew instantly and correctly until I figured the problem out. So the little box seems okay

Are the bulbs wired in series, so one bad one could knock out the whole shebang? Or could the dimmer have been damaged, or died on it's own?

I can see to drive now, but it's frustrating to not be able to use any creature comforts safely at night, without literally pulling over and using the map light. I guess if a proper wiring guru shows up, I also need a hand with my ignition circut, but that's another matter.

[Hijacker]

They should be in parallel, but there's only one or two bulbs inside the unit. It uses a plastic diffuser to spread the illumination light.

[mechanicalmoron]

They should be in parallel, but there's only one or two bulbs inside the unit. It uses a plastic diffuser to spread the illumination light.

Yeah, I looked behind my radio, they're not lighting at all.

I also pulled out my dimmer switch and tested it, the ohms change the same amount on the different pins, when it's operated either direction, so it can be assumed to work.

I tried grounding the red wire with yellow stripe, which is the lighting wire. Cluster stayed lit, nothing else came on.

I read there are fusible links behind the kick-panel? I couldn't find em. I did find 2 relays and 2 black canister things that I couldn't figure out how to unlatch to remove, so I don't know if that stuff works or could be the problem (in a vertical row, between the fuze box and the firewall).

My TCU does have a scratched trace and a few that look browned that are next to the one that went bad originally, but they all look like they're probably conducting, though I was to stupid to check for continuity, I'll do that tomorrow.

So yeah.... cluster lights work, little green indicator LEDs (like on climate sliders, or cruise button) work, but button backlights and climate backlights don't work, dimmer doesn't work, and it's driving me nuts.

[biggie]

Did you not just try swapping the TCU? I have a couple extra if you need one.

[mechanicalmoron]

Did you not just try swapping the TCU? I have a couple extra if you need one.

I didn't, I don't have access to any.

If you'd like to sell one that you can verify as good, I'd be very interested in that.

[biggie]

Both I have we're in good cars. Just pm me.

[mechanicalmoron]

Both I have we're in good cars. Just pm me.

I'll let you know, going to try to fix mine tomorrow, if I can find a problem with a multimeter.

But I appriciate it, and may well take you up on it. I can't think what else would be broken that could cause this.

[mechanicalmoron]

bump.

I took the TCU out, and tested all the traces that could have been problems, and they all seem fine. The capacitors have different resistances, but I don't know how they work, or if that's to be expected. I think I checked everything in line with the power transistor, that could have blown.... Anyone with a background in electronics have any suggestions? Is it likely there's an undetectable problem with it, and replacing it will fix it?

Or anyone who's done some dash wiring work, and knows how the whole thing's controlled? Any particular grounds or hidden fuses or anything that I could have burned out when I originally blew the tcu?

[cole d]

I know this is old but did you ever fix the problem? I've been reading old thread all day trying to figure out what is causing my issue and most are unanswered so I assume a bunch of 240 are driving around without cluster/dash lights?