My wipers quite last week on my crewcab...89 wiring. But my problem was in the wiper control on the turn signal stock. It's been rattling, and making odd clicking sounds, and would wipe erraticly, been like this for a couple years now. I knew it would die eventually, but never took any steps to prevent it either.
I have a spare steering column, from a 90/91, with the same wiper control. So I figured I'd use that. Swapped it out yesterday ....and nothing!! I thought maybe it was the wiper motor. So I pulled the motor and tested it...no problems there. So I pulled the new'er stuff back out and compared the old vs the new. Turns out the wiring for the 90/91 is a bit different. Plugs are the same, actual control stock is exactly the same...save for a couple wire that are a different color...but the whole wiring system is set up differently.
Last night I decided to cut and paste my two systems. Use the new'er control stock, and the old wiring. Carefully made sure to match all the wires to the proper connections, and solderd them all together. Will try installing it this morning...hope for the best.