Thanks to Trucker22 and Scrout for responding to my question. The relay tested OK. So ordered a new compressor form "Parts for Less" in Tucson, AZ. The cost was USD $185 plus $20 shipping (5 days to Ontario, Canada). The dealer here wanted $595 for the compressor and 180 for the drier. Also, they wanted $85 to diagnose the problem. So I saved hundreds thanks to this site and posts by Sturge and others who made the remove and replace clear and simple.