77 300D KLIMA into 85 300TD
 

Will it fit and work? I'm looking at a CWC candidate w/ broke HVAC.

Maybe I don't understand your terms but a 77 300D doesn't have a Klima relay.

If you mean to move the ACC system from a 77 to an 85, banging your head against the wall repeatedly will give you the same results for less cost. Slightly less painful than banging your head against the wall is learning the 85 ACC system and repairing it. Resoldering the PBU and replacing the actuator pods usually gets things going.

Sixto
87 300D