Dash cluster illumination do not work?

Well those are all powered through the same system and the idea is that the dash lights not coming on tells you that you also have no tail lights, been a GM feature for a very long time (since the early 50's). Step one is to verify that the rear nodule has power on fuse 27, it feeds the rear integration module and if it has no power you lose those lights. Use a cheap incandescent test light to check for power on both sides of the fuse. It should have full time power. It feeds into a relay (#40) that is controlled by the Dash integration module and the headlight switch, when triggered on it feeds power to the lights you are missing. To see if the relay is the issue you will need a length of wire with a 10 amp fuse in it. To use it go to the three fuses that feed the lights from the relay, those are the left and right park fuses and the DiMeR fuse all in the same fuse box. First turn on the lights to park, test those three fuses for power on both sides, I'm betting there won't be any. Now pull those three fuses. Get your fused lead and the test light. Connect the test light to a good power source and touch it to the fuse terminals one at a time. One side should do nothing the other side should light as the light finds a ground through the light bulbs and circuits. Now connect the jumper lead to battery power and go one at a time and touch it to the fuse contacts while watching the light and the fuse. Do the lights now come on? Yes for all three = the relay (#40) or it's control circuit is the problem. On your car that relay may be replaceable, I don't recall what year they soldered it in place. Did one of them blow the fuse? Yes = you have a short in that circuit and it burnt the relay. Try the testing to see where the issue is. If relay 40 will pull out of the box then you could try replacing it, but if there is a problem in a circuit it may just fail again.

I will post an image of the fuse box but images have not been working so we will see if it shows up.