Hopefully can help me. I have nothing on dash(Speedometer, gas, etc). Sometimes I got to play with the radio also to get it to work. Is it a relay, fuse or what? Where do I start?

there could be several reasons wy the lights don't work, bulbs blown, loose wire, fuses, interior light dimmer switch turned down all the way (oh yes this has happened before and the owner took his car to the garage to fix it!!!)
I would start with checking the fuses and work your way up also check with a voltmeter if there is current at the fuse. check all groundwires attached inside.
and that radio is on a different circuit (fuse) so the two have nothing in comon with each other

i would think that if the display on the radio occasionally works, then it must be a loose wire either between the dimmer and the dash bulbs, or between the radio and the dash bulbs, you'll notice on most cars that the dimmer knob also controls the brightness of the display on the radio.

Unless it's a fuse, you're looking at taking the dash apart, or atleast the instument cluster apart. On most cars this is no easy task!

The dash instruments are lit up by a vacuum fluorescent display inside the instrument cluster. There is a separate power supply module for this part of the dash that may have gone out. It is something that will have to be replaced with a salvage yard part. Repair of the old one may be possible if there is still a repair depot servicing these.

The radio is inside another electronic module mounted under the left side of the console. It feeds information to and takes commands from the video screen on the graphics display unit. Troubleshooting pages from the shop manual are needed to get going on this problem.

I can send you some exceprts from the manual on both these areas. The electronics on this car are extremely complex. There is a computer, power supply, fuse box, or electrical module behind just about every piece of interior trim on this model.

The complete shop manual is still available from Helm. Go to www.helminc.com (http://www.helminc.com) This is the company that prints them for GM. At $75. this would be a wise purchase if you plan to keep the car and work on it yourself. It covers all 86 Buicks and amounts to a mountain of paper.

Resolder the CPS Module located above brake pedal

The dash instruments are lit up by a vacuum fluorescent display inside the instrument cluster. There is a separate power supply module for this part of the dash that may have gone out. It is something that will have to be replaced with a salvage yard part. Repair of the old one may be possible if there is still a repair depot servicing these.

The radio is inside another electronic module mounted under the left side of the console. It feeds information to and takes commands from the video screen on the graphics display unit. Troubleshooting pages from the shop manual are needed to get going on this problem.

I can send you some exceprts from the manual on both these areas. The electronics on this car are extremely complex. There is a computer, power supply, fuse box, or electrical module behind just about every piece of interior trim on this model.

The complete shop manual is still available from Helm. Go to www.helminc.com (http://www.helminc.com) This is the company that prints them for GM. At $75. this would be a wise purchase if you plan to keep the car and work on it yourself. It covers all 86 Buicks and amounts to a mountain of paper.

I agree with Todd's response. Had to resolder large component traces on intermittent CPS which put me in dark and cold no heater in 10 degree drive for 500 miles. No problems since (7 years))

my 87 has the same problem. can anyone tell me what the cps module looks like? or where exactly needs to be resoldiered? there are alot of wires and i cant tell whats what. Thanks aj