This vehicle came in with the complaint that the blower motor would work sometimes but recently it had gotten to where it did not work at all. I hardly ever see vehicles this old in my shop anymore. This is one problem that I have fixed dozens if not hundreds of times over the years but I have never gotten the chance to perform it since I started this site. It is a little odd in that it covers so many years, makes and models of GM vehicles. I know that it goes all of the way back to the 1960’s and well through the 1980’s. I think there may be some that still used this setup in the 1990’s. Whether it was a Buick, Chevrolet, Cadillac, GMC, Oldsmobile or Pontiac, if there was an option for factory air conditioning for a particular vehicle it has this connector. The diagnosis always starts the same. Customer states that there is a blower issue. Testing finds that the blower fuse is good and powered with the key on but there is no ignition power at the blower motor, blower resistor, blower switch or the mode switch. By the time you have gotten to checking for ignition power at the mode and blower switches you are very close to the real problem.
Behind the HVAC control panel you will find a single brown wire with a two piece black connector body. It will generally be between six and eighteeen inches from the back of the control assembly.
There you will find signs of heat build up either in the wiring insulation, the plastic connector bodies or both.
The repair is simple enough. Cut the damaged connector out and splice the two wires back together.
I use seamless terminals and heat shrink tubing to insulate the terminal.