Hi I am new here and getting somewhat desperate about this problem.

I have a 1990 Chevrolet Silverado with the engine running I turn on the
lights and all the dashboard gauges turn of, both the turn signal warning lights come on continuous and I have no dashboard illumination lights. I have also checked it with the engine turned of when I turn on the lights the temp gauge goes all the way across to the right, both turn signal warning lights come on the dash, for awhile if I banged on the top of the dashboard the problem corrected itself now it doesn't, I have just taken the dashboard of, cleaned all electrical connections thinking I had bad connections but still have the problem after putting it all together again can anybody help as I am just stuck for a possible problem and this is my only vehicle so I am unable to drive it at night.

 

sounds like a bad guage cluster

 

I had been wondering myself about the cluster gauges having a problem but all gauges work okay with the lights off.
I just tried taking the fuse out of the panel lights at the fuse box and everything works okay except I don't have any panel lights if that is any help in helping me to fix the problem, I checked all the other fuses in the fuse box and they are all okay, when I had the dash cluster out previously I did check every bulb I could get to to make sure they were not blown I think I may take the cluster out again and just go ahead and replace all bulbs in it incase one of them has developed a short as they are all the original bulbs and the truck has done 343.000 miles and I bought it new early in 1990 and I am surprised the dash bulbs lasted this long.
Please keep the suggestions coming I appreciate all suggestions and will try every suggestion as I just don't want to have to replace the truck for an electrical fault that should be fixable.
When I do manage to fix this I will post what the cause of the problem was, I will be phoning around the local truck salvage yards in the morning and finding out if a replacement dash cluster is available as I am sure a new one would cost more than the truck is worth.

 

I had a similiar problem on an early 80's Silverado that we restored and it ended up having a broken ground wire under the dash. On those years there is few ground wires together under the drivers side dash panel. It would do all kind of funky stuff and had me scratching my head for a couple weeks. Both turn signals would illuminate when I hit the brake, some of the guages would dance all over the place, etc. A broken or corroded ground will do some real weird stuff! Just a thought.

 

I had forgot about the guage cluster ground issue the early chevys had that makes sense............I have a 67-87 chevy repair manuel here if you think the grounds are somewhat the same I can look at that for you.

 

Chris I would appreciate that thanks, I will still be digging around myself to see if I can find the problem I appreciate all help I can get and I am not the kind of person to sit and wait hopeing someone comes up with the answer, I still wonder if your original suggestion about the cluster mount may not be the problem somewhere in the printed circuit board built into the back of the cluster mount that plugs into the main feed wiring due to the fact that banging the top of the dash made it fix itself for awhile suggesting a bad contact somewhere in the dash within or close by the dash pod as I call it.

 

possible.....but a bad ground would also do the same thing.......the ground would be where I started first.....a guage cluster is a "guess" at this point

 

Hey guys I found after checking every ground I could find that the contact between the back of the cluster and the socket it fits into is bad I managed to fix it for now but don't know how long it will last it seems as if the socket that is clipped into the actual dash as in I am guessing part of the wiring harness had some bad contacts so I used fine picks to tighten up the individual contacts and when I put the cluster back in it all worked my guess is the bad contacts was causing feed back in the same way as bad ground would.
Thanks all for your help I am going to keep my eyes open for a used behind dash wiring harness should the problem come back as well as another cluster case, talk about a big headache obviously when I banged the dash in the past it remade the contacts until constant banging made the contacts open up too much.