Ahnenerbe

I have a 1989 with what I believe is a common problem, but after checking Batee and forums I still can't quite find the answer. My problem is this: my dash lights up pretty well during the day, I do have a bulb out, but I can see the dash very well. At night it stays lit pretty well, until I turn on the lights. When this happens the dash goes dark, and I cant see squat. Many have pointed to fuses and light switch, I checked fuses, they are good. I bought a used light switch and cleaned it up, did not fix issue. Is there anything else I should be testing or looking at? Thanks for your help!!

Hot Rod Roy

Probably a dumb question, but when you twist the light switch ****, does anything change?

Ahnenerbe

No, on both the original and the used one I replaced it with, when you turn it there is no diming effect.

383vett

When the lights are on and the dash is dim, what happens when you shine a light on the photocell?

Ahnenerbe

I will do that tonight, have not tried that yet.

xrav22

Have you checked that your clear window isn't dull. I had mine apart to put a new lense and used wax and buffed the clear piece of plastic and my digi dash was much brighter during the day as the light was able to get thru

gerardvg

Hi
From your description the dash seems to work ok during the day when the photocell adjusts the display brightness, do the lights dim when you put your finger over the photocell?
That pretty much will confirm all is ok with the dash.

The headlight switch gives the lights on input to the dash, also the variable resistance by turning the headlight **** goes to the dash for lights illumination as well as the radio center console and wiper light.

My 85 shop manual shows the Inst fuse supplies the light switch, also mentions to look at the fuse block details....
See link to Batees diagrams ... note the external display brightness control is the photocell...

In my case I had an issue with the dash pcb boards interconnecting pins was making the lights go off and on over bumps.

Good luck it should be a simple bad connection somewhere, simple AFTER you find it.

Link to Batees wiring diagrams below.

http://www.batee.com/corvette/dcrg/wiringdiagrams/

Ahnenerbe

Went out and tried the flashlight on the photo cell. With lights on, dash is so dim it can't be seen, when light hits the cell dash comes on like normal. Also the dimmer switch does not do a thing, not sure if it's a separate issue or not but there it is.

xrav22

Just went out also at night, start the car dash is at medium bright, turn on headlights and dash is high bright and the dimmer does dim dash and switch pod not alot but a bit.
During the day the dash is not real bright but you can cee all the gauges. Can you take a pic?

Cliff Harris

This thread might have some useful information in it:

http://forums.corvetteforum.com/c4-t...ull-story.html

Ahnenerbe

That's quite a write up Cliff, thanks for taking the time to post. I really am not that inclined to start tearing the unit apart, but since the dash lights up at night when a light hits the photo cell, wonder if it's possible to override the cell?

GRIS

Had the same problem with my '87. Was not the headlight switch or photo cell, was the dash cluster. Batee refurbished the cluster and it looks better than when I bought the car. Brian is the guy to go to!