This is my first time here, GREAT SITE!!!!! here's my problem....

My dash lights have not worked since i bought my baby, a 1987 formula. I found the fix for that on here. My dash board is completely removed. so it was easy to remove the npn transistor. i have a similar yet beefier transistor here at the house so i swapped it into the circuit. It worked, i then went back to the stock one and discovered that it worked just fine it was only loose to begin with. then i turned the dash on and grounded the black wire that was hanging loose from where i disconnected it from the plastic dash, the lights in my cluster glowed super bright and everything appeared to work perfectly, but when i turned the dimmer down past halfway it started burning, literally!!!!!!! smoking and melting. but when i roll the dimmer back up the lights come back on with just a tiny bit of dimming when you try and adjust it down towards dimmer it starts smoking then if you turn it all the way down it just burns up. NOW, when i disconnect that black ground wire, it stops burning, both blinkers and the flashers come on and stay on and the dash lights are on but barely visable, and when you turn on the dome light the cluster lights glow super bright again and the others go out. Sorry for the long post but i am doing a complete restoration on my baby after an engine compartment fire. Burning and melting scare me. I have 3 switches to open the lights, and 3 dimmer switches also. 1 set is out of an 82 firebird s/e and i was told they are slightly different as the do not use a transistor. I did try them both the switch and the dimmer yeild the same results, its the 82 dimmer that is different as it has big ol heat sink while the other 2 87's do not. The 82's does not seem to smoke as bad but i do not trust it. Please and thank you to anyone who can help!!!!!!!!!!!
Chuck