Hi - hopefully posting in correct spot, I'm a newbie. Trying to help my 85-year old dad fix his air con issue on his 2007 RX350 with 140k on the clock. Airconditioner blows air, but only mildly cold (ambient temp is 93F, vent temp is 55 after about 5 minutes at idle, setting is on "LO"). I can't hear the compressor kicking on/off. After a few more minutes, vent temp goes up to 75 and does not improve. I checked freon level and it seems ok (Lowside pressure is bouncing between 35 and 42, high pressure is steady at 170). No leaks detected. I see freon cycling through in the observation window near low-side pipe. Running diagnostics on display in the cabin, error code "24" shows up.

Any help or tips how to troubleshoot or repair this issue? Thank you very much and happy to join this forum!

--Joe in PA--