Rear A/C blowing hot

[anguyen325]

Hey guys, i just recently put a new a/c compressor, front evaporator core, dryer and expansion valve on my 02 yukon 5.3. I havent had any problems for the last 2 months but recently the rear a/c stopped blowing cold. The front a/c is still ice cold though. Any thought on what might be wrong? Thanks.

Alan

 

[Phantom240]

Check to see if the evaporator is getting cold. If it's not cooling, then I would venture to guess you have an expansion valve/orifice tube clogged. Why did you replace all those parts? If it was a failure of the compressor, then it probably sent trash through the system and made it's way to the orifice/expansion valve.

I just had to replace the orifice tube on my OBS because the rear would get cold, but the front wouldn't. It was all gummed up, and it wasn't even related to any sort of other component failure.

 

[Yukon Lover]

on my 03 yukon the blend door actuator doesnt change from cold to hot when you turn the knob up front. It could be that. it can be the actuator or theres a controller too. they both are in the rear behind the passenger side plastic over the wheel well. you can remove the actuator and turn the blend door to see if you get a temp change. My local junkyard let me try an actuator and the other one didnt turn either so i know it isnt that but havent tried the controller yet.

 

[anguyen325]

this is actually the 3rd a/c compressor i've put in my car. it was previously a customer's car and she sold it to us after she brought her car to pepboys and they put a 102 amp alternator instead of the 130 amp which caused the entire fusebox to melt. so i sat there for 3 days soldering wire by wire. not bad for only $400 LOL but even when she had it, there was this mysterious leak that would lead to the compressor locking up. When i finally changed it the last time, i smelled the a/c line cleaner in the car and we finally found the leak was coming from the front evaporator core. We pretty much changed everything on that care except for the front evap core and the condenser. The a/c hasn't given me problems yet and havent detected any freeon leaks so it should be fine. Guessing it's probably the rear expansion valve since i just changed the front one.

---------- Post added at 10:27 PM ---------- Previous post was at 10:25 PM ----------

i actually thought it might be an acuator problem. I'll probably get underneath the car to see if the line is getting cold. If it is, it has to be an actuator problem. If not, guess i gotta get a new expansion valve lol probably check the fuses tomorrow just in case too

 

[Phantom240]

Didn't know the newer body style had both heat and a/c in the rear, lol. I've got an OBS.

 

[Yukon Lover]

Yup, adjustable temp like the front

 

[NC_John]

The a/c hasn't given me problems yet and havent detected any freeon leaks so it should be fine. Guessing it's probably the rear expansion valve since i just changed the front one.

---------- Post added at 10:27 PM ---------- Previous post was at 10:25 PM ----------

i actually thought it might be an acuator problem. I'll probably get underneath the car to see if the line is getting cold. If it is, it has to be an actuator problem. If not, guess i gotta get a new expansion valve lol probably check the fuses tomorrow just in case too

Did you get this sorted out? I noticed last week that the rear air isn't working on my 02 (my wife drives it and didn't report the issue to the maintenance department - me). Did the whole changeout of parts last fall when my compressor started locking up (clutch was failing). Didn't change any parts for the rear. Front is nice and cold- rear, not so much.

 

[anguyen325]

not yet. I havent had time since ive been between working at my dad's shop and the hospital. When i do work at the shop, we're always slammed with work so i never have time to work on my own car. I narrowed it down to the rear expansion valve. Bought the part only $25 at advanced so gonna try that out. Just not looking forward to ripping apart the rear panel to get to it. Will try it soon to narrow down the problem.

I actually had the same problem with the compressor locking up. When replacing the compressor, i found out the A/C clutch pulley was broken so i replaced that. Problem now there's this weird noise when i turn the A/C on. I took the fan shroud off and it looks like the A/C clutch doesnt want to engage which is causing the A/C clutch pulley to vibrate. My dad said it might be the A/C relay, so i replaced it with no improvement. The noise resolves after the engine heats up. Any ideas what could be wrong? The entire system is basically brand new so maybe a defect?

---------- Post added at 11:46 PM ---------- Previous post was at 11:43 PM ----------

BTW, not having rear A/C sucks b/c it takes twice as long to get the car to a nice cool temp. Makes it feel like the a/c isnt even working at times!

 

[NC_John]

The freon was too low in mine (down 1.5 lbs). Both front and back are ice cold now. It looks like I lost the freon through one of the Schrader valves over the winter (which I identified by the dye in the system).

 

[anguyen325]

Finally got around to working on the A/C and replaced the expansion valve and orifice tube and boy was that shit a pain in the ass!! Quick connect heater hoses my ass!! Such a misnomer! Plus my orifice tube was clogged up with a bunch of metal which I'm guessing was from residual metal from the last time the compressor blew despite flushing out the system multiple times with the proper cleaning solution before installing the new one. Anyways, when i first charged the system, the rear didn't get cold so i started freaking out and cursing. My cousin told me i should maybe drive around and see if the freeon gets pushed to the rear. Low and behold, i have rear A/C again!!