Last October I replaced the AC Compressor, Dryer, and AC Relay on my '89 300E. Fine until now. Without warning the cold air stopped, blower kept working.

Investigation showed pressure, and fuses okay, however AC Comp did not engage. I replaced the AC Relay with another Relay, started working right away, I thought it was solved (bad relay).

The new relay lated only about 5 minutes and smoked. Any ideas why I have blown the AC Relay?

Thanks

Rusty