I have a 2011 TL SH-AWD. My problem is, I think THE AC should blow colder air than what it's currently putting out. I think the AC compressor might be the culprit. The compressor is cycling on an off but it's very loud and my RPMs fluctuates quite a bit. If I'm standing outside of the car I can visibly see the tag lights flicker from dim to normal. I brought a can of AC pro, and when I hooked it up to the system it was reading fine. Could it be the alternator? Any help with pointing me in the right direction would be greatly appreciated.

 

yes, you should troubleshoot the A/C system, instead of going in blind with the ACpro can.
First step is to troubleshoot the relay. I assume it;s good, since the compressor is kicking on.
next, check the compressor clutch to see if it;s engaging.
then use your gauge that came with the acpro can and hook it up to see if the pressure is correct.
you can also check the power going to the compressor clutch with a multimeter to check for power.

 

okay, I'll be back with the results. Thanks for the help I appreciate it.

 

The pressure is at 30 psi

 

Did you ever figure this out? I’d like to get my A/C blowing colder.