Here is the solution to my A/C Motor blower issue: When the problem originally started I bought an after market speed control/resistor switch from Auto Zone. When that didn't work I changed the fan motor (also after market from AutoZone). After that I took it to a Ford Dealership two different times. They ordered an HVAC module after the first visit. I brought the car back to them but after they changed it I was informed it didn't fix the problem either. I took the car back because it was the weekend and they wouldn't be working on it anyway. After looking over the electrical diagrams checking all fuses and relays again and again, I came to the conclusion that one of the parts I purchase had to be bad from stock (autozone). I removed the fan and used a 12v car battery to test it. Worked fine. I removed the speed control resistor switch and compared ohm readings with the original motorcraft switch. I then went back to the dealership's parts department and they let me take some resistance measurements on a new OEM switch. The ohm readings on my original switch and the one from the dealership were nearly identical. So long story short.... I installed the original speed control resistor switch and WA LA! AC worky worky. I have the ohm readings from a good switch and can post them if anyone needs them. But my main recommendation is to change the motor fan first or change both in pairs. I have read a few different articles/blogs that mentioned a bad motor can put an excessive electric load on a "NEW" resistor/speed control switch and burn it out. I don't think this was the case for me. Im 99% sure it was bad from the manufacturer. Why? because if my original faulty blower motor took out the new speed control switch why didnt it take out the original motorcraft switch? With that said, I would also recommend OEM parts. And I really hate saying that, because they can sometimes be 3 times more expensive. To be perfectly honest none of the components were not hard to replace. (especially after doing it three times, LOL). The last time took me less then 10 minutes. The blower is right behind the glove compartment, and the access cover (dampener) was actually the hardest thing to remove. (three screws). The blower motor has one screw and then you just turn it CCW and it falls out. The speed control switch (2 screws), is behind where the blower motor lives and easily accessible with the blower motor out of the way. The HVAC module is mounted on the right side of the wall behind the carpet and trim under the right side of the glove compartment. (two screws). Im in my mid 50s and don't like working on cars much anymore, but it really wasn't that bad, and very happy I figured it out. I apologize for being long winded but I hope this information helps someone else out there. I love my MKS and glad there is a place to exchange information.
