Instrument lights dead

[soundguy]

Removed the instrument panel today. All the connections look good and appear to be solid. No broken wires I can see. As long as I had the whole thing apart, I replaced nearly all the bulbs. Went back together easily enough, but still have the original problem- no backlights on the Tach, speedo, temp/fuel gauges. So driving at night can't see any of that. The small lights within each of those are working ( high beams, turn signals, etc )

Any ideas what to try next? Thanks.

[KevinH1990]

Originally Posted by soundguy

Any ideas what to try next? Thanks.

Another weak point in the lighting system is the light switch. Mine wasn't turning on the headlights. I removed the switch and soaked it with electrical contact cleaner. That solved the problem, and it hasn't returned for several years. (Of course, now that I have written that the problem may recur.)

I suggest that you clean the light switch like I did and see whether that helps.

Good luck.

[soundguy]

Thanks Kevin for the suggestion. I installed a new light switch about a year ago, so hopefully it hasn't gone bad already, but maybe I'll pop it out and clean it.

[KevinH1990]

Originally Posted by soundguy

I installed a new light switch about a year ago,

That seems to decrease the likelihood of a faulty switch.

Given your description of the symptoms leading up to the failure, (i.e. The instrument lights have never been as bright as I'd like, even with the dimmer turned all the way up ) is it possible that the dimmer switch in the cluster has gone bad? This YouTube video shows someone working on a Mercedes cluster with a bad dimmer switch. https://www.youtube.com/watch?v=itzEX3ow5uY I couldn't find one for Porsche.

You may want to spray contact cleaner on the dimmer switch or gently play around with it to see if that helps. If that fails, consider contacting an instrument cluster repair shop (e.g. Palo Alto Speedometer) ask them whether they are aware of dimmer switch failure on 986 or 996 clusters.

[soundguy]

The dimmer switch seems to be working as it does still dim the LCDs under the tach, speedo, and fuel gauges. Good suggestion Kevin and maybe a little contact cleaner is in order. I am getting pretty good at taking it all apart at this point...

[muledog]

Replacing the headlamp switch fixed the lack of instrument lights for me. Similarly, I pulled apart the instrument cluster and found no problem but a new switch fixed it.

[redpepperracing]

Originally Posted by soundguy

Removed the instrument panel today. All the connections look good and appear to be solid. No broken wires I can see. As long as I had the whole thing apart, I replaced nearly all the bulbs. Went back together easily enough, but still have the original problem- no backlights on the Tach, speedo, temp/fuel gauges. So driving at night can't see any of that. The small lights within each of those are working ( high beams, turn signals, etc )

Any ideas what to try next? Thanks.

The bulbs for the tach, speedo and temp/fuel gauges are different from the other bulbs, did you replace them with the green based ones or black? I mistakenly used the black ones and they didn't work, once I put in the green ones they worked.

Something to try, anyway.

[soundguy]

Yes, I replaced the 2 green bulbs, but no joy. It's very strange, since the 2 green bulbs seem to be the only ones not working. Probably going to take it apart AGAIN tomorrow and look closer at the boards and ribbon connectors.

I really appreciate people still chiming in with ideas. Thanks all.

[soundguy]

Turned out to be the ignition switch. Crazy that a failing ignition switch would cause such a minor and specific problem. Oh well, back in business!

Thank you everyone for your help. And thank you Pelican for this awesome community.