I have installed a Honeywell TZ-4K zoning kit. Everything works except the AC. I don't know where to attach the call wire for the outside compressor. If I couple it with the cooling(yellow) wire, the Honeywell unit switches the 24v over to the heat(white) wire. Does this wire need to go back to the central(HVAC) unit.

All the instructions for this system are included in the many pages of documentation that comes with the kit.

Here is all the information you will need.

http://customer.honeywell.com/techlit/pdf/68-0000s/68-0259.pdf