AC not working on 1993 Volvo 940

The compressor is not engaging. When AC button is pushed. Where is the ac relay is located
in a 940 Volvo turbo

1 answer
I don't think there's a relay for the A/C Compressor, the power comes from the control head. I would consult a wiring diagram to be sure.
Verify you have power coming from the control head, I've seen several of them fail.