Greg5OH

OK gentlemen, help me walk thru this AC issue. Pretty cheesed i have ZERO AC in this 2000 ls400.
I have no idea when it comes to AC systems, what to check, pressures, etc.

Heres what I know.
-PO said he had the AC topped up 2 years ago, said it was great last summer. I now have ZERO cooling. Buttons inside light up and are plugged in. All of the other HVAC options work fine.
-I quickly pressed the schrader valve on the...expansion tank? located at the front of the car beside the front electrical fan. Seems there is enough pressure in there.
-What do now? I will verify if the compressor actually turns on-however I have a feeling it is not turning on. How to check that, and what do I do if it is indeed not turning on?

Greg5OH

also what should Hi and low pressures be?
whats the weight of R134a the system should take when completely vacuumed?

kevvo

You might not have enough gas. If it was "topped up" 2 years ago it suggests a leak. I don't know about the LS400 but some other cars have a low pressure cut-out switch near the thermal expansion valve. Not enough gas and no go, to protect the compressor.

If indeed the 400 has such a switch, and after finding out from other contributors here that it is absolutely safe to do so, temporarily and very briefly jumper the switch. If the compressor clutch then engages, a lack of gas is to be investigated.

cgawelko

I say go to a shop and have them recover, reoil and recharge your system with a touch of PAG dye in there. Just incase the A/C goes weak, you already have the UV dye in it to find the leak.

Greg5OH

true. Im goign to have my buddy vacuum it down and put some dye in it and recharge the system, hes a commercial HVAC guy. has r134a onboard.
Whats the system capacity?
Also does the ocf20 have on board diagnostics for AC system like the UCF10 where you press a few buttons together to read the codes?