A/C compressor questions

[n55luvr]

New to me 04 LC has a nice feature called blow ambient air when A/C is on. So I'm trying to do a little troubleshooting. PO said he had 2 lines replaced last year (and I see where they spliced in new sections) and it was blowing ice cold last fall.

When I engage A/C and put it on a colder temp or even MAX COOL I never feel the compressor kick on. Usually I can feel when the compressor engages and maybe even notice a slight jump in RPMs, even on our new BWMs I can feel this. On the LC, it does absolutely nothing when I toggle A/C on and off.

Assuming I have another leak somewhere and all refrigerant has leaked out, would this prevent the compressor from being engaged? Is the system smart enough to know this? I mean maybe I have a bad A/C clutch rather than the scenario mentioned above but I doubt that is the case.

Any ideas?

 

[parnoren]

Refrigerant must be present before the compressor can kick in.
I had the same thing happening and the dealership added a dye to the refrigerant to find yet another hole after I changed out one of the lines.

 

[PADDO]

Yes, zero refrigerant = no go. The refrigerant also carries the small charge of lube oil, if you've dumped all refrigerant a pressure switch prohibits the compressor engaging for self protection. You can check the status of the switch to see if it's closed or open. The AC section of the FSM in the stickies is pretty good and easy to follow. Bush mechanics would stick a small charge in and see what happens, but if you've lost charge the system really needs to be repaired and evacuated before recharging.

 

[n55luvr]

Perfect, exactly what I was wanting to hear. Evac, refill and possible hole patch is much easier for me to digest than a broke compressor, clutch or other buried mechanical device.

Thanks again guys!!

 

[onpoint01]

If you have a leak you may not be able to hold a vacuum on the Evac. I would try to evacuate and if successful recharge and add a can of refrigerant that has dye in it. This will make finding the leak much easier using a UV light. You could also try pressurizing the system with nitrogen but if its a pin hold this could be difficult to find.