Recently I noticed that my air was getting a little warmer but didn't think much about it. The car is not a daily driver anymore and only has 88K miles on it with the original r12 set up. When I was out the other day for a ride the air started blowing hot, the A/C lights on the dash began to blink and I knew I had a problem. Being it was a very slow leak, I tried to do the R134 retrofit to the car. Here is what has been done.
The remaining R12 was evacuated from the system.
I put the new R134 fitting on the high and low pressure side of the system.
I fired up the car with the air on max and attached a bottle of r134 but the compressor never would kick on
I ended up hot wiring the compressor to the battery to make it run and finished adding 2 addl bottles of r134 w/ oil in hopes I could get the pressue to come up and have the hi/low pressue switch activate the compressor--no dice

Any thoughts on what is next?? ANY help is much appreciated thanks

 

Once it sets the low gas code - which is what the blinking is/was all about - it isn't going to run. Clear it by disconnecting and reconnecting the battery. That should get it running. And if panel starts blinking again, go here: https://www.corvetteforum.com/techti...=193&TopicID=2

 

ed.:

Do what Mr suncr says...

 

Sun CR you are a genius I just went out and did that and it works fine Feels like winter in FL all over again thanks for the tip
Saved me a trip to the shop

 

Glad you fixed it - had you gone to a shop, they may not have known that this was all that was needed, so if you ever end up at one, make sure that they do this.

 

Hi SunCr...You are certainly an expert on a/c. I have been on vacation and have not fixed my a/c yet. Trying not to pay mechanic all my S.S.check. I have a 94 and compressor's clutch not grabbing. Checked code,is 00. Have disconnected battery,no change.Pls tell me where is the low pressure line so I can check pressure. I'm a new 'vette owner. Thanks much.

 

I don't know if I'm an expert, but every GM I've owned seems to have left the Factory with the a/c going downhill.

With no CCM or Control Panel codes, it may have plenty of gas - or it may have lost everything that was in it while sitting (it has to run for a code to set) - or there was some catastrophic event like a snapped line or a stone through the Condensor. Doubt you have the latter since it's fairly easy to see either of these problems, but if you have a Scanner, a low voltage return from the Pressure Sensor (meaning no gas) may have set a PCM code for that sensor (assuming your Year uses that programming), so you could quickly scan it or see if you can retrieve anything via the Instrument Distplay. And you might just go ahead and disconnect and reconnect the battery again just to make sure that some glitch isn't hanging something up somewhere. Now if it does have plenty of gas but the Relay isn't getting driven (grounded)by the PCM, there may only be a poor connection at the Low Pressure Switch. Here's what I suggest you do:

Find the Low Pressure Line which is the larger line (on top) exiting the Evaporator Case or that big plastic piece jutting out on the Passenger Side Firewall. Just after that line exits the case, you'll find the Low Pressure Switch. Disconnect the harness and with a DVM, see if the switch terminals show a completed circuit. If so, there's enough refrigerent in it to make it run and if you put a paper clip across the terminals of the Low Pressure Switch Harness, that should turn on the Compressor. If it does, plug it back in and hold the connector onto the switch and then wriggle it around. If this gets it running, replace the switch and/or the connector. If it doesn't run with a paper clip across the harness terminals, try jumpering each side of the harness to ground. If the Relay is good, one or the other should make the compressor run. If it doesn't, replace the Relay. Then if replacing the Relay doesn't solve it, you should scan it to see if the PCM is getting an a/c request, but you should go ahead and see what these things do for you first and then repost.

 

Hi SunCr...Thanks for your fast reply. You are very knowledgeable !

 

Let me try my luck. I have a 86 and the AC only blows on high. I have changed the resistor and the blower motor switch. Same thing. One of the vacuum hoses is loose right rear of plenum which someone said may be the problem. No one can tell me where it hooks to from there. Any help would be appreciated.

 

You should start a new thread - blower speed has nothing to do with vacuum. Assuming you have a Manual Unit, juice flows from the Blower Switch through the Resistor Pod for each position except High. Therefore, one wire - for each position except High - at the Pod should have battery voltage for each position; the output something less. At High, the juice flows directly to the Relay and onto the Blower Motor. That part is working correctly. Check the Pod voltages with a DVM, but it sounds like your '86 needs a new Blower Switch. Use to be servicable item, may be out of production. Check www.acdelco.com under HVAC for your Year.