Ok, here's my latest "issue" :D I just got my A/C compressor replaced last October and the mech. refilled the freon as well. Since it has been hot out lately I have been using the A/C, while driving down the street it is cold but when I come to a stop the A/C blows warm air. Sometimes in the morning when it is cold and I have the heater on 80* it blows cold air, and sometimes it blows hot. Also, when sitting at an idle with the A/C on the idle changes alot, I know when the clutch engages it will change the idle but it does it alot more than what I consider normal.

Any help is always appreciated. :thumbs:

 

Don't ya just love the HVAC systems in our cars? :D :rolleyes:
There have been so many guys posting on these things. Oh GM :rolleyes: strikes again.
Do ya have the electronic control climate C68 option?
Does the blower motor itself work? Can ya hear it run? Parked, not moving. How is it's fuse? If that checks out OK, maybe verify door movement by removing this in the passenger side engine compartment:
lookdown inside and try to see this:
See the link in yellow? It's plastic. It can break and leave that door flapping back and forth between air passing thru the heater core or air passing thru the A/C condenser thing. I guess you could stick in a long antenna or something to see if the door is loose or won't move. How is the vac line that feeds that system? Sometimes the old brittle lines develop cracks/vac leaks and the system won't operate correctly? Check that vac line feeding it from off of the intake manifold and especially where it comes off that check valve.
If ok, how is vac to the diaphragm motor that pushes the rod on the door(the circled in yellow plastic piece is at the end of that rod.
How are the resistors on the control unit?
original thread with resistor values---->http://forums.corvetteforum.com/zerothread?id=202649
could be the head unit in dash. Try cleaning it's contacts per Jim 65ZO1's procedure. Check his excellent webpage.
That cycling of the clutch sounds wrong. Does it bog the motor down when it kicks in? Another real sharp guy is SunCr. He knows lots on this. You there? :D





[Modified by 89 Paul in Cal, 3:51 AM 5/28/2003]

 

Yeah, I'm here, but your pictures & hints say alot - wow! My guess would be it's either the door problem you've covered or pressure related; restricted orifice tube. On an older system, especially one that's been leaking, little pieces of metal get trapped in the orifice screen, restricting flow, especially at low compressor speeds; hence some cold air at speed, but warm air at idle and the compressor will be cycling (it shouldn't cycle at idle above 70 degrees). A/C pressures are the best way to tell - the high side will be too high & the low side will be too low, so to speak, assuming a full charge. If the door is ok, check your operating pressures. If the system was topped off or repaired without cleaning/replacing the orifice, that could be your problem. And if it is, don't feel too bad. I found out the hard way after rebuilding a compressor & not replacing one. The orifice is in the vertical tube at the bottom of the Evaporator. Unfortunately, if it needs to be replaced, you have to discharge the system.

 

Just noted your in CA - B.A.R. is interested in protecting consumers from crappy a/c repairs (it's the biggest complaint they get) and there are some regs in your favor. If that compressor was replaced in the last year, check your invoice to see what was done. Shop should cover a discharge, evacuation & recharge if they didn't flush the system, replace/clean the orifice & swap out the Accumulator on a Compressor replacement. If not, find the # for the B.A.R. in your Yellow Pages & file a complaint.

 

GREAT info, thanks to both of you guys for all of this. I'll definately troubleshoot the system with your tips this weekend. When my mech replaced the compressor he did flush the system and replace the orifice, so I'm gonna start with the door and then move on from there. The main problem of clutch cycling is when the system is set under 70*, but sometimes it will blow cold air when set to 75 or 80.

Thanks again, once again, proof that this place is the best! :thumbs: