Heat blower will not operate?

I checked all of the fuses and relays first. Since asking the question, I went ahead and tested the voltage being supplied to the blower motor control module which tested at 12.1V. This told me that at least one of my problems was there, as a max of 8.3v was being supplied the blower motor when the fan speed was on high. Replacing the module fixed the problem. I did also source a used HVAC control head to hopefully fix the other issues with the system, I have not installed it yet. A note for this job is the module for the auto climate control will cost $175.00 to $250.00. You will wish you had the control knobs! You also will need to be proficient at using a multi-meter to test to narrow down the possibilities. The only info I could get for the tests was very technical written test procedures from the Ford dealership system.

Thanks. Yes, They were very reluctant at the dealership to give the information I needed but having gone to high school with the service manager helped my cause. My next truck will be a stripped down work truck. Appreciate your help.