So I may have made some bad assumptions. There is a relay for the ac compressor under the hood in my '98 V70. It has a hot line in (term 3) and two terminals (numbers 1 and 2) between a coil that read 13+V. The relay suggest that when I turn the AC on at the climate control on the dash - that either the number 1 or 2 terminal would ground out creating a voltage drop through the coil which would induce a magnetic field capable of "closing" a switch which connects terminal 3 to terminal 5. Terminal 5 goes to the compressor.

My thought was that my climate control was bad - since I did not get a voltage drop when I activated the AC on button. THIS IS WHERE I THINK I MADE A BAD ASSUMPTION. I decided to bypass this stuff (since the climate control units are very expensive) so I put a switch in that would connect Terminal 3 to Terminal 5 - thus powering up the compressor.

As a side - I first thought that my coolant was low - when I took it in the shop said I had plenty of charge and that the problem was somewhere else.

Well once I added the switch I had a nice cold AC for a week. But today my wife thought the car was overheating (the AC bypass switch was on) when a bunch of white "smoke" started pouring out from under the hood. Since I've determined that the car did not overheat I think that I activated some high pressure release valve and dumped some of the coolant.

So - question is - is the AC relay that I bypassed controlled by several systems? Meaning does the AC on button on the climate control talk to a pressure (high or low) sensor - or any other sensors prior to activating the AC relay? If so, then my climate control could be good - and the problem could be with a sensor, or with the charge still?

Also, does anyone know if I caused any permanent damage by bypassing the ac relay? I'm stumped and concerned that my actions may have caused me much bigger problems. Any help or insight or suggestions are welcomed.