Digi dash light issue
 

Headlights off the dash lights up. headlights on and the dash lights may come on but can go dark after 30 minutes and all that is lit is the gear selector and digital display in the center of the instrument cluster.

Use the dimmer wheel to make the display brighter or dimmer works on all the other lights, not the instrument panel.

Ideas?

See the thread 89GT Pod Lights Out - Center Console On.

Thanks - I'll start there and report back.

Disconnected 2 pin connector, attached multimeter to connector and set to volts:

Test results:
Key off:
Dial all the way to the left 10.37v
Dial all the way to the right 8.48v

Key on:
Dial all the way to the left 9.74v
Dial all the way to the right 7.93v

I just took a look at the wiring diagrams. What does your central locking button backlighting do when the problem occurs? You say, "Use the dimmer wheel to make the display brighter or dimmer works on all the other lights, not the instrument panel." Does that include the central locking button?

The answer to that would narrow things down a bit.

You should also measure and report the resistance of the caged resistor.

Some additional data points:
Power supply to the resistor grounded to the door arrestor:
Dial all the way to the right
IGN OFF ON OFF ON
LTS OFF OFF ON ON
0v 8.68v .064 8.36v

We're interested in assuring that there's electrical continuity along the yellow-highlighted path.

https://cimg0.ibsrv.net/gimg/rennlis...00c79e2916.png

https://cimg1.ibsrv.net/gimg/rennlis...4832d8bee4.png

[QUOTE=Ed Scherer;15463168]I just took a look at the wiring diagrams. What does your central locking button backlighting do when the problem occurs? You say, "Use the dimmer wheel to make the display brighter or dimmer works on all the other lights, not the instrument panel." Does that include the central locking button?
Yes
The answer to that would narrow things down a bit.

You should also measure and report the resistance of the caged resistor.
5.0

/QUOTE]

The central locking button backlighting working OK when the instrument cluster backlighting eliminates connector T5 as a potential problem.

Also... make sure you check the "ash tray / instrument lights" fuse (it's #9 on my '90; I'm not sure what model year car you're troubleshooting). Pull that fuse and make sure the contacts are OK and apply DeoxIT if you have any. Maybe replace the fuse (or exchange it with another), just to be sure.

And I'd like to add an oddity.... Ignition on, lights off PSD lit brightly, turn the lights on and PSD light goes almost dark.

Where is the T5 connector?

I'll check and clean the fuses.

10.5 volts directly on the CE panel contact @ fuse#9. That is a bit low, right? Other fuses show 11.7 with the engine off and key on.