Your temperature blend door in the car may not be moving. Try turning the vent on (no AC) with medium speed, then change the temperature control from full hot to full cold, and you should hear the sound and speed of the air change slightly as it goes to full hot. The temperature blend door, if it works correctly, will force the air to go through the heater core when you turn it to hot, affecting the air flow. If nothing changes, then that actuator is not working.

 

Also, while A/C operation and components don't change much you should check the forums for your later model W-body (or even later ??Omega) v. our older B-bodies, for any design issues or known foibles that have come to light = weak quality oem sensors or actuators or pressure switches.... Those more often become newly discovered trouble spots specific to each new platform.

 

Thank you both!

 

The temperature blend door, if it works correctly, will force the air to go through the heater core when you turn it to hot...

When I do this the air from dashboard vents definitely gets much hotter. Still no AC though.

 

And the temperature of the engine compartment AC metal pipe going into the firewall should be COLD

 

Thanks MWP.
Yes, the low pressure pipe through the firewall is cold.

 

Well, I increased the fluid pressure to 35 psi and now it's working fine.

Quite a surprise!