So my fan speed **** was acting up. I purchased a remanufactured unit from eBay. It was working great except the heat didn't seem to work as good. So I got a Dorman part from work just to test it. But when I plugged that one in, the fan speed **** did not work at all. I plugged the remanufactured unit in and the fan speed didn't work either.

As I was testing things I found the 4 wire plug that plugs in on one side must not be making a good connection. if I wiggled the wires everything would work. So I ordered a new harness from work. But I noticed that the back of the module doesn't appear to have pins that contact inside the harness. I looked at a new Dorman part and it looks the same way. What is the harness contacting to make the electrical connection?

Is everyone's module like this?

 

well, in case anyone runs into this problem.....apparently that plug does nothing for the module. i guess it's for either other features or for modules in other trucks that have different options.

i unplugged the harness completely and was still able to turn on the blower motor. i guess i have a loose connection on the main plug b/c if i tilt the module a certain way, it does not work. but i was able to get everything back together and working so i'm happy.