I had my S70 at the dealer today. They determined that an error code indicated that the "line pressure switch" was not functioning correctly. They replaced it and the compressor is now functioning. The switch they replaced is what davidmk31 shows in the photo posted on the previous page of...

Thanks for the advice, abscate. I'll do a visual inspection to see if I can find any cracks, etc. I'll mention this, too, in case you think it might be related: When I pulled the radio out from the dashboard, I noticed that the solid red wire extending from the back of the Electronic Climate Control...

Update: I forgot to mention that I swapped the relay out with a new one, and the AC compressor still did not run. I also swapped out the ECC from above the radio with one from the salvage yard, and that did not fix the problem either (although I don't know if that salvaged ECC had problems.)

My 98 S70 has the exact same symptoms that robl245 describes. My mechanic can also get compressor to run by bypassing the relay. He confirmed the high and low pressure switches work. Additional testing lead him to believe there is a short somewhere. In his words, he believes "the quad driver in...