Just got a 99 LHS and the ac will not work. It just stayed on high fan and all of the other functions worked except the ac. after reading on here and other sites,It seemed to be the ATC module. I replaced it with one I got on ebay. the thing operates the same as the old one except that the fan works like it should and I can turn it off. but the ac will not work. Is there something I have missed? any help would be nice.

 

Freon level? Current to compressor? Low pressure switch?

 

according to the previous owner the problem had just started about a month before I got it. I'll have to check those when the car gets home. can you point me to the low pressure switch?