When there is high humidity or rain, my dash lights do not work. In addition to that the LED clock dims.
I have replaced the headlight switch and the entire instrument cluster with no luck.
Typically, when the dash lights do not work, neither do the tail lights. However, the tail lights work fine.
Does anyone have a clue?
I just got this car off ebay. It was in really good shape except for dash lights and a broken header panel that I just replaced. It looks as if some monkey mechanic just ripped the dash apart. Most of the inner connectors for the bezel are broken and the entire bezel just pulls right out.

 

Hello,
Did you ever figure out your dash light issue?
I am not sure how the dash lights are powered as I have not consulted my EVTM and shop manuals. There are relays in the engine compartment that might control the dash lights. You mention changing the headlamp switch, but have you checked the dash light dimmer rheostat as well? I would guess that the dash light dimmer rheostat would get power from the headlamp switch, and then reduce the voltage according to setting to the dash lights. You mention that the clock on the dash dims when you turn the headlamps on. Does it dim according to the setting of the dash lamp dimmer setting? The clock gets a signal from the dimmer rheostat so that it will dim according to the level of light on the dash. I would start with checking ALL connections in the circuit for corrosion and such. Did the car come from a high humidity environment? I live in the desert in SE Washington state, and we do not suffer from most of the issues that high humidity climates do.
As for the dash plastic parts, they are somewhat fragile. I know I have done R & R work on the tabs that hold everything in place. The dash bezels, etc. that I have had to R & R are made of ABS plastic. As such, I have repaired the broken parts with black ABS cement and fiberglass fabric strips, much like you would repair fiberglass with resin and fiberglass fabric or mat. In the case of the ABS dash parts, use the ABS cement as the "resin" and the glass fabric to provide strength. Works great. You can't be in a hurry and you have to think through what you are trying to repair and take it one small section at a time. My dash used to creak and squeak a lot. Not so much any more because I repaired the cracks in the plastic.
I mention the EVTM and shop manuals. These are worth their weight in gold as they are vey comprehensive in describing how things are wired. You need to study the first few pages of the EVTM when chasing a particular circuit. The introductory pages will tell you how to read and follow a circuit in the EVTM diagrams. It is worth the time.
Let us know how it is going.