My 2005 TL won't blow cold. There's hissing coming from the vents when I press the a/c button to enable the system. I also checked the low and high pressure and the low is around 40, but the high has no pressure what so ever! What could be wrong? How do I properly inspect pressure for both low and high lines? Procedure?

 

I'm burning up! Someone please help me! lol!

 

Okay, I was finally able to hook up the gauges and run the procedure right. At 3k rpm the low side is at 40 psi and the high side is at about 80-85. Am I out of freon? bad compressor?

 

Bump, anyone?

 

No, your low side pressure is fine. Your high side pressure is also good and the compressor works. Do not put anymore freon in the system. Did you see the compressor cycles on and off frequently? If it does not stay on for a few minutes, it may be the compressor clutch. It should come on and run for a while before turning off. You did not mention if your evaporator/vent fan is working. Does it just blow warm air or not blow any air at all? If it blow warm air, it could be a relay or the temperature control sensor issue. If you have an OBDII code reader, it may give you a code. If not, you will likely have to bring it in to the dealer for diagnostics.

 

accordman: How can I tell if the evap fan is working? It just blows warm air... I also have a high side valve leak.. I rechecked the high side pressure and it is almost 0 psi and the compress wont kick on anymore

Can I switch out the high side valve of there is no more psi on the high side? Also do I just hook up the scanner and run for codes like a CEL?

 

If it's not one thing, I swear it's another thing.. Stupide AC is driving me Nuts!! LOL

 

Ugh, that is no good. Your AC system is now empty. It appears that you leaks all your freon. I would either order the new high side pipe that have the valve or get one from the local salvage yard. Replace that pipe first and make sure that it seals properly (don't over tighten it). You will need to bring into a shop to recharge your AC. The reason is they will need to vacuum out all the air and test for leak before they put the new freon and oil in. You would not have the equipment to do it yourself. If you just put freon in, you leave the air in the system and you may not know if it may leak somewhere else. You will also need to add AC oil to lubricate the compressor plus you still have moisture in the system. You may be back to square one in a few days.