Whew,, just finished replacing mine.. (1994 Chevy G20) I had the same problem!
Mine had some type of red oil/gunk all over it, the contacts were worn down too! This isn't hard, just very time consuming!!! 4-5hrs min!! -- DISCONNECT THE BATTERY -- Bright lights will help you see under the dash!! 1st. remove engine cover(gives you more room to work). 2nd. remove the dash(at least enough to get under it with your hands and provide visual). You will have to undo the speedo cluster. If you have big hands its going to be a little harder(I do). The board is located with the motor. It is held in place by 3 small torx screws. I used a 1/4 drive with 3 - 6" extensions and a universal joint with the torx bit. I put electrical tape around the u-joint to keep it from flopping around! The electrical connection clip is on the left side, remove the connection BEFORE you undo the screws! The motor/board is located against the firewall, between the engine compartment and the steering column area. You do not have to remove the wiper motor!!!! Once you can see the black cover, the rest will be obvious if you are mechanically inclined. I used some silicone sealant to help hold things in place ( put some on the alignment slot area of the board and the top edge of the cover - let it dry until its very tacky - it will stay in place better!) I wish you luck, its time consuming!!! Not hard!
Mine work fine now!!
