AC does not work
 

The AC on our 98 S90 is not working. The fan works but there is only hot air. I realize that the refrigerant might be low. If that is not the problem where should I look?

Thanks, Pete

You'd need to measure the refridgerant pressure. You can do so with a refill kit that has a pressure gauge. It attaches to the low pressure side (usually the fittings are difference for low and high pressure so if your refill kit fits, you are on the correct port. To measure the pressure the AC compressor needs to be running - so you may need to jumper the low pressure sensor to trick the car into thinking the pressure is ok. Look for a sensor with wire on the AC return like somewhere between the firewall and the low pressure fill port (not sure about the S90s but its on the passenger side on the FWD models.) Plenty of how to vids on Youtube so best to start there to see if you have the tools and skills.

As a quick test, you can try jumpering the low pressure sensor (ie use a paper clip to connect the two leads in the wire connector) to see if that will make the compressor kick on. If yes, then you need to recharge the system. If not you may have a compressor issue or something electrical (ie temp sensor etc).