I'm helping a neighbor with his X5. Here is wht he says is going on...

The A/C on the bimmer isn't blowing cold air. With max A/C engaged, the air coming from the vents is the same as the ambient air temp. It's the same for all other A/C settings, too. The system's never been recharged so I thought that was the culprit. I bought an r-134a recharge kit with an integrated gauge, but when I hooked it up to the low side the pressure reading was in the red; about 115psi if the gauge can be trusted. I was expecting 45psi or less. A/C was on Max and the engine at normal operating temperature when I attempted the recharge. I checked the compressor clutch and it is engaging when the A/C is turned on.

Any ideas on where to start?

Is the condenser fan spinning??

Or if the gauge is correct it is way over charged. If that is the fact release the refrigerant out of the low pressure side due to this is the vapor side the high side is all liquid and very dangerous (well if you don't get out of the way fast enough). hope those two things work or at least gives you a little starting point..

First two thoughts were bad expansion valve, or overcharged system. If it hasn't been charged recently, then probably the expansion valve is stuck closed.

The aux fan not coming on might also cause that problem. But usually, you'd get cold air from the vents for a bit until the system got hot and the fan was unable to cool it down. It sounds here like you're just not getting anything to begin with.

What about internal compressor damage. I have seen lots of these over the years. Just because the clutch is spinning does not mean the compressor is spinning inside.

Having 115 on low side to me sounds a bad compressor when engaged, What does the high side read, If it reads 115 also than your compressor is HISTORY.