AC compressor of my '89 Xj won't work. Somehow the power supply line is not getting the juice. Where it's coming from? A module? AC relay?

Also where is the AC relay for th vehicle. I didn't see it on HVAC system on pasenger side....

The A/C relay is on the 4 relay block, passenger side, on wheel well under hood. there should be a plastic cover that reads "relay center"
The A/C relay is closest to the firewall (furthest from the front).