Instrument lights not working?

[pauls]

92 Toronado. No instrument lights when headlights come on. Dash dimmer switch will turn on the interior lights. Other lights work on dash like the data center with odometer, eng data, radio etc. Looked at the fuse box in Glove comp, int lights fuse OK. Any other fuses or somthing under the hood to check?

[pauls]

Would a bad LED light on the steering controls cause all instrument lights not to work? Are the Steering wheel lights behind the buttons needed to complete the circut?

[Twilight Fenrir]

If I recall from my '89, they're not led's but very tiny incandescent bulbs. I reme,ber working on my wheel comtrols, but I had the digital dash, so I have no idea how the xluster lights function, sorry.

You'll just have to chase the problem, find the light and see if its getting power, if not move along the wire to the next component... I gave my service manual away with my car when I sold it, so I couldn't tell you specifics. But they have a diagnostics tree for just about every problem, it might be worth your time to get one on eBay, they're an invaluable tool for these exotic vehicles.

[torolist001]

92 Toronado. No instrument lights when headlights come on. Dash dimmer switch will turn on the interior lights. Other lights work on dash like the data center with odometer, eng data, radio etc. Looked at the fuse box in Glove comp, int lights fuse OK. Any other fuses or somthing under the hood to check?

If I understand you aright, dimming is working ok (for the data center say), but not in the IPC and other areas (e.g. doors)? If so, that suggests that the main parts of the control circuit are working (the sun sensor has to work for example).

The lights are incandescent. IIRC, there is a big transistor in the IPC that provides the current for many of the lamps round the body, not just the IPC. Perhaps that has blown. This sounds tricky to diagnose. In diagnostics, are the various switches and dimmer slider reporting plausible numbers?

If they are, suspect the IPC, at least for further testing.

HTHs

[pauls]

I've got the lights working again. Replaced the fuse which was not blown in the first inspection, but the new one got things working. But dash lights only work with the twilight system on. Still do not work when you turn on headlights manually.

[Twilight Fenrir]

I've got the lights working again. Replaced the fuse which was not blown in the first inspection, but the new one got things working. But dash lights only work with the twilight system on. Still do not work when you turn on headlights manually.

Sounds like a computer issue to me No idea which one though, that bloody thing has so many...

[torolist001]

I've got the lights working again. Replaced the fuse which was not blown in the first inspection, but the new one got things working. But dash lights only work with the twilight system on. Still do not work when you turn on headlights manually.

Glad you found the fault. You might want to pull and replace all the fuses, over time the connections can become corroded and the action of pulling and replacing the fuse cleans it up. You will lose any memory settings if you do this, the PCM will have to re-learn too.

That the dash lights only work in darkness is correct. They are controlled by outside light levels, not the headlamp switch. If the twilight sentinel sensor fails you might find the dash is dimmed right down in daylight, at first you might think the VIC has failed (assuming you have one), when it is just very dim and in bright light it looks like it is off.