UK Car Repair: Jaguar Air and Heat, xj40, vdp

Question
Hello,
I recently switch the engine out of my 1988 Jaguar VDP and put it into a 1990 xj6 sovereign.  My heat doesn't work, at least it doesn't blow through the vents.  My A/C comes on, but it doesn't blow through the vents either, and it definitely doesn't get cold.  Would it have anything to do with the switching of engines?  Please help.  Thank you.

Answer
Was the 88 a 4.0 from an XJ40 or a 4.2 from a series 3?  Regardless the harnesses on the cars are different and presuming the system worked beforehand it has to be something not connected or wrongly connected.  You just have to back-track and check all of the connections.