960 Dash Lights - Continuing Intermittence, Mostly Inop

[zippinbye]

The 960 has had problematic dash lights since it arrived at our home last fall. It could be said that they are intermittent, but they have gone from working most often to working rarely. Early on, I sensed a correlation between key cycling and the problem. My daughter caught on to that, and simply tried restarting many times until the lights came on. After a bit of research, I thought I had a slam-dunk solution. Brand-new ignition switch; no luck. Replacement dimmer switch (used, known to function at time of removal); no luck. I took the 960 to an indie shop to resolve an engine roughness problem that ended up being a sticking EGR valve. I asked them to take a look at the dash lights. They were convinced a new headlight switch would fix the problem, but couldn't find one. I acquired a used, tested dash light switch. I noticed the dash lights come on immediately after installation, but there was some variance in the brightness. I cycled the dimmer switch and it worked as expected (no faulty behavior as I have seen in worn rheostats, such as jumpiness or dead spots). But the dash light intensity still fluctuated from time to time when not messing with the dimmer. However, the illumination was continuous for several on/off test cycles. Elated at my apparent success, I handed the keys back to my girl for a night time drive. First try ... no dash lights. Damn! Back to square one. I should also mention that some relatively uninformed probing with a multimeter seems to confirm power interruption at the dimmer switch, along with expected variable resistance in relation to adjusting the dimmer. Another thing, I do not sense any of the telltale signs of a run of the mill "short." No reaction to bumps, shakes and turns. Just sometimes the dash lights work, sometimes they don't. And the original perceived relationship with cycling the ignition seems to have disappeared or was simply not the case all along. So I am wondering what other electrical component should be considered. Is there a resistor, ballast or some other item that could be contributing to the part-time dash lights? I'd appreciate any thoughts.

[jimmy57]

There is a square module on the back of the instrument cluster that is the instrument and other item illumination controller. The lights are not a simple 1-12V resistor circuit. The module pulses the feed to the lights at a variable percentage to get the voltage control to dim the lights. The module may be loose or defective. I think you can put your hand on it with the under-dahs panel and corrugated knee bolster removed. To change it would require removal of cluster as I don't thonk the duct behind cluster woulkd allow you to manipulate a screwdriver.

[rgk]

How about the fuse box? Are all of your fuses clean and are the fuse terminals clean?