Hey guys,
Take the wire to the compressor clutch and add a 2 way on/off switch...you could do it on the power or the ground side, it doesn't matter. Set your temp control to a/c all the time, this will engage the high speed fan relay to kick the fans on then turn the switch off to the clutch to disengage the a/c. Your fan will run at high speed all the time while the a/c head is turned on. If you want the a/c on, all you will have to do is flip the switch to allow the circuit to be completed and your a/c will work like normal. If you tap in the fan relays you can run into issues with high and low speed fan operation, defrost operation, and a/c operation. I can be done that way, but you have feed back issues between the fan relays. I have set up relays to run the fan while the car is off between rounds at the race track with a switch which is nice , but it runs the battery down fast. The way I said above lets the pcm do its job without changing anything...the only thing you are doing is turning the clutch on and off manually.
Later,
Joe