I drive a 2001 Volvo V70 wagon and have been having an issue with the a/c. I’ve brought it to the dealership numerous times, but they haven’t been able to fix the problem. Here it is: after driving the car for 1 to 1.5 hours with the a/c on, the a/c seems to fall off. I have to crank it up to full blast to even get a small draft of cool air coming out on the recirculation setting. If I switch it to the fresh air setting, it makes a hissing noise and almost no air comes out. When I shut it off completely for 15-20 minutes, it seems to work again, but this is a less than ideal solution given the heat wave we are experiencing. Please help!
The next time this occurs pull off the road and turn the motor off by moving the ignition key all the way to the off position. Then restart the motor. If the AC is back to normal then you have the same issue I had with my '98 V70XC.
I learned how to turn off the motor and restart it while moving and it “reset” my AC every time. The real fix was a new AC control unit. The part I ordered on ebay and mine was easy to change out. I pulled the radio unit, then the AC unit was easy to pop out. You just plug in the new unit and install it. My problem was solved. Of course that Volvo had numerous expensive repairs and I sold it due to excessive repair costs.
I’m not sure if your 2001 has the same dashboard set up as my '98. If you go to Volvo for a new AC controller be ready for one of those $1,000+ repair bills.