HUMTECH---you da man!!
Got the relay from the GMC dealer 25 miles away--local didn't have it. Got home and it wouldn't fit. I had asked for a ECAS relay for '03 Hummer H2. This time I followed my own long standing rule---take the part with you-- and they swapped it out. He looked it up again, and showed me where his data base had it wrong. Anyway, the correct part # is 15319851. I installed relay, put the fuse back in and ...bingo...we have air. I think it had to readjust itself or something because initially the compressor did not turn on. It didn't air up to normal ride height until I drove to work. Everything appears to be back to normal. Thanks again for the advice from all you guys---I was really dreading troubleshooting all that plumbing.
