Tach not working, no heat, no dash or Instrument panel lights
 

I recently got my 81 300 SD working and find I do not have any, instrument cluster lights, dash lights, tach, and heat. Any suggestions on any of these would be greatly appreciated.

Have you checked and cleaned the fuse and fuse connections? I had a headlight go dim and left side parking lights go out. Dirty connection was all it was.

Do what rrgrassi said - then do a "search" here on the forum for MONOVALVE

You almost assuredly have a blown or loose or non-making-contact fuse.

Use the search at the top of the forum section, try each item, you'll have lots of reading.

It's been almost a year since I fixed mine, which had the same problem as yours. If the fuses check OK, take the cluster apart and look for a broken jumper between the 2 PC boards, also look for other broken bd soldering joints, The dimmer is most likely broken aslo, just bypass it by soldering on a jumper for full cluster brightness.

thnaks
 

Thanks for the suggestions, I needed the directions. I will check out the suggestions.

My dash lights came on after I repeatly turned my brightness swicth on and off.