A/C compressor relay on '85 300D?

[Fredmburgess]

A/C compressor relay on '85 300D?
My buddy's got an '85 and can't get the A/C to run. Pressure switch and charge are good, cold air if he hot wires the compressor clutch. He's looking for a relay in the compressor circuit. Is there one? If so where? Other ideas?

Thanks.
Fred

...oh yeah, I want to help him out because he just donated a good used trans to get me back on the road. I'll do the manual conversion next time! fmb