The upper display. Where you read outside air temp/ mileage, Etc. Is there a fuse for this? mine is out.

 

This should be in your owners manual. If you don't have one, you should be able to download one.

 

Isn't there a way to toggle that display setting between on and off? I sold off the Blazer a while back, but going from memory, thought I had turned that display off once. . . . Could it be that simple? Seem smore likely than a fuse., IMO.

 

You can turn it off by sequentially pressing the mode button that also cycles the display through all of its readings.

 

I understand the functions of the buttons. The display is dark. no matter what i do or push.

 

Due to the proximity to the roof and the lack of insulation above it, those modules are starting to have a reputation for going out on the older rigs among us due to heat stress induced failure. Try adjusting your cab dimmer switch and see if you can see anything at all, and failing that i will try to find a wiring diagram for it so i can point you in the right direction for diagnostics.

 

thank you

 

Fuse block and DIC wiring diagrams
RDO IGN (fuse 24) supplies 12 volt supply for DIC