07 expedition a.c. fan works sometimes
 

I have a 07 xlt el expedition. The a.c. control keeps losing ground, preventing it from working. It will work sometimes. I replaced the blend door actuator because it was knocking. I've replaced the control module also. Does anybody know what might be wrong?

Would you mind telling us how you determined it was losing the ground?
How far back did you check for having ground and then losing it?

my mechanic tested the module and said it was bad, so I replaced it. It worked until I started the vehicle the next morning. It came on in about 20 minutes into my drive.

thanks for the help