A/C Blowing Hot Air

[ddjames]

The A/C in my wife’s ‘03 X5 3.0i (123K mi) is blowing hot air at highway speeds and at idle. Had the FSR replaced about 3 years ago but the system has never been recharged. I figured the culprit was low refrigerant so I picked up an Interdynamics R-134a recharge kit with built-in gauge. When I got home I went for a test drive and confirmed the wife’s observations.
I did a visual when I got back and noted the compressor clutch was engaging with the a/c on max. Also, the aux fan was coming on about every 30 seconds for 10-20 seconds.
With the engine at normal operating temperature and a/c on MAX setting, I connected the recharge kit to the low side. I expected the gauge to be in the green but was surprised to see it in the red. About 115psi if the gauge can be trusted. I don’t have a manifold gauge set to measure the high side. Outside temp was 87.
I’m stumped. Searched the E53 forum posts and didn’t find anything similar. Any explanations why such a high pressure reading on the low side and suggestions for repairing?
Thanks!