Need AC Work... but where?

[armcomdes]

The AC on my 2007 ES350 needs some attention (not cooling). I have recommendations on some honest local mechanics, but would a dealership be better equipped to handle a Lexus AC issue specifically? 

I've recharged the system a few times. Recently replaced a relay (to no avail). Now the system won't take a recharge because the compressor isn't engaging, which could be an issue with different relay, switch or sensor.

Is this an issue a Car Diagnostic Scanner could find?

Thanks in advance

[RX400h]

Some AC troubleshooting tips:
 

 

[armcomdes]

Followed the info in the video. Had to bypass the relay to activate the compressor so I could add refrigerant. Compressor works fine. Got it to almost the green zone.  Relay now is working and half the car has cold air. My next step would be to find the leak using the dye/black light process.

This guy's vid shows how to use the dye. Question is am I up to replacing a condenser (if that's what is leaking). It's a big hob.