VetteNoob

Well, we replaced EVERYTHING in the retrofit project. Compressor, dryer/accumulator, o-rings, orifice tube, blah, blah, blah..... Took it in today to have a vacuum pulled and charged. The controller will not engage the compressor. The mechanic manually overrided the controller and filled the system. Still nothing. The fan doesnt blow, the compressor wont engage. All switches in the lines were replaced. However, I did notice that the main fan is on all the time now. It doesnt turn off. Almost like the head pressure switch harness was pulled off. Any suggestions as to what to look for? I have the electronic climate control AC system. Or should I just take it to a Vette shop and say PLEASE FIX MY A/C! TIA :sad:

MrJay

Mine would not kick on until I reset the computer maybe you just have to do that to get it going.

Jay

xzvs

disconnect the battery and let it sit for 5 mins --try it again and see if it works --it coulda set a fault code.

ZylaRace

One switch is the high pressure switch. This should be closed (zero Ohms) under all normal operating conditions. High Pressure Switch [Located on the small Evaporator pipe OPEN: 430 psi CLOSED: 200 psi
The other switch is the low pressure cycling switch. This is the one that you need to jumper when filling a system. I think that system even has a third switch to turn on the fan, if not, the cycling switch does that also, in shich case the fan should only come on w/ the compressor is engaged. Cycling switch is OPEN when freon pressure is below 24 psi and CLOSED when freon is above 47 psi.
What are your switch's doing? How many do you have, 2 or 3? What is your high side pressure? What is your low side pressure.

ZylaRace

BTW The early C4 ac's don't interact w/ the ECM, only the climate contol system. i.e. No trouble codes to check/set

VetteNoob

I have 3 switches. All 3 were replaced with new GM switches. IF I read the gauges correctly when the mechanic was charging it, it almost looked like the low side was around 40 and the high side was only 150ish. Im not sure. However, the blower also stopped blowing air from the vents when he was done. I did check the fuses and the AC fuse (25 amp) was blown. I replaced it, but still nothing.

SunCr

There is another 5 amp fuse protecting the blower motor circuit which on electronic air also controls the a/c clutch. It's mounted on the evaporator housing or the firewall in a small plastic box about an inch square. Leads should be purple. The person who charged the system should have turned down (one turn counter clockwise on the adjustment screw) the low pressure switch so that the system cycles at 19 to 21psi if you went with R134. Make sure the fan switch is hooked up - if it's disconnected the fan will stay on - I disconnect it to keep the fan on during charging. It's mounted on the high pressure (smaller) line to the Evaporator. It's lead is dark green. The other switch mounted next to it is the high pressure cut out. Leads for that switch are light green and black.

ZylaRace

Please clarify "still nothing".
You hit the AC, set it to max-cold,... the compressor does not engauge, the vent blow warm air, the fan does not engauge?

Do you have a OHM meter? Is the high pressure (small tube) switch CLOSED? Is the fan switch (small tube I think) OPEN? The cycling switch (big tube) is OPEN or CLOSED?

How the cycling sw works: The compressor is turned ON (cycle sw closed), until the low pressure side of the compressor circuit is less than 24 psi. (If the correct amount of freon is in the system, it is all in the liquid state on the high pressure side of circuit. i.e Turn off the compressor.) Then stays OFF until the low pressure circuit is more than 47 psi. (There is now enough gas on the low pressure side to turn ON the compressor.)

Do you know how much freon he put in?

ZylaRace

Can you measure the pressure on the system when it is in the neutral state? i.e. Has not run for an hour?
If it is less than 24psi,.... you don't have enough freon in it.

When you jumper the cycling switch connections does the compressor engauge? After a minute, does the fan engauge?

VetteNoob

Thanks for all the suggestions and the help you're giving me. All the fuses were checked (that I know of, including the 5amp fuse). The blower is not blowing at all. All wiring harnesses are plugged in. I think the programmer may be fried. :sad: GF mandated I take it in into Austin Corvette's this morning, got tired of throwing money at parts hoping I find the fix. It will cost me more, but it should be fixed right and I wont have to bear the Texas heat too much longer.

Thanks for all the suggestions though. Im sure Ill have other issues I will need help with that I may be better capable of fixing on my own.

VetteNoob

$280 later AC is fixed. Well, sort of. Looks like the module that controls the compressor and blower was fried and I had a bad ground to the blower. Now to the sort of part. The air only blows through the defrost and by my feet. I can live with this until I have more money to blow. It is either the programmer or some vacuum source being messed up. I think it is the programmer since it was working before the other mechanic shorted the fuse jumping the compressor :mad .

85WHITEZ51

Did you tell them that that is not working yet. Austin Corvette is very good about doing the right thing. If your AC works like mine the location of where the air goes to is controled by a little actuator rod that connects to a flap under the dash. If it works the same I could fix that for you.

VetteNoob

They suspected it is either a vacuum problem or the programmer, but that diag was on top of the $280 charged for the electrical work they did. I told them to stop seeing that it is actually blowing cold air now. I think it is the programmer since the other mech who charged the system blew a fuse jumping the compressor. I think that probably fried my programmer. It was working before the fuse blew. :mad Aint no way I can prove it so...my tough luck this time around.

85WHITEZ51

Was it a mechanic at austin corvette?

VetteNoob

It was Eddie, the shop foreman.

CoolVette86

Sorry to hear about your A/C problems... :( My guess would be towards the programmer also, since you've already replaced the module. My module broke also last year, and I took it to my mech right away since I did as much non-technical diagnostics as possible and knew that it's probably something that only professionals can detect. Good luck to you.

PTz-92-LT1

If you decide it is a A/C Programmer, call Jeff Kipp at 1 (800)728-8267, $102.76. It is a AC Delco reman. All of the local dealers around my area wanted between $75 and $100 more.

If you do change it out, take the tiny nut off the the used programmer, below the manifold and use it in the place of the locking clip that you have to mangle to get off.