03 Camry - low idle and stalls

I replaced the a/c relay with success on my '03 Camry, but the idle speed has decreased significantly and the engine stalls. When I changed the relay, I disconnected the negative battery terminal during the relay change and reconnected once the new relay was in place. The low idle/stalling problem coincided with the a/c relay change. Any suggestions? BTW - the battery tested fine. I also put the old relay back with the same problem.