Volvo vt 880 A/C

Did you ever change the orifice tube/expansion valve?

It can get clogged up over time and cause erratic temperature changes in your system.

Additionally anytime you replace the compressor, you should also replace the receiver drier that is by the firewall.

 

Volvos are infamous for electric problems. I drove one that had a wire broken in the loom, and would make intermittent contact so the a/c would work in the shop, but not on the road. In the end the mechanic bypassed the loom and ran wires to the switches.

What it sounds like is yours isn't shutting off, and the evaporator is freezing over, blocking airflow. The thermostats may be bad or the wiring broken. Try this, at about 15 minutes, turn off the a/c, but not the fan. Turn it back on about 5 minutes later. If it stays cool, that probably is your problem.