HVAC controls

First I want to thank everyone who has replied lately in helping me,now my question today is, what do I have to disconnect to take the control module out of the dash board? I took it out as much as I could and saw the temp control wire with what looks like a small "hat" installed at the factory keeping the wire from coming off. How can I disconnect this and still be able to re-attach it later? My fan control wiring is messed up and I need to take the unit out, because for some reason my doors controlling air movement aren't working either. I have received much help from this forum figuring problems out on my '92 Blazer.
Thanks again,

George 748