It's actually been like this for a while.
since I've lived in the Pacific Northwest, I've not needed my A/c a whole lot.
apparently, it's a use it or lose it thing, because I lost it.
It no longer blows cold. The fan itself works fine, but it's just air.
I hit the button for A/C and the light comes on, although every once and a while it'll blink and turn off. I hooked up a 134 gauge, and it read 70 Degrees ambient (I think, that was a few months ago, but I know it had refigerant in it)

any ideas?

 

when i bought my car the first thing i did was have the refrigerant flushed and filled and now it get's pretty cold
the gm stuff just doesn't get the job done

 

what?

 

Hi, We can get this figured out, but need a bit more info. Is your unit Manual, or Dual zone Automatic temp control?. When you turn the AC on, is the compressor actually running? If the light blinks and goes off the comp is not running. This can mean a few things. Also when you say the 134 guage reads 70 degrees ambient, I'm not sure what you mean. If you are talking about a set of refrigerant guages, they read in psig, and have a hi and low side, in a properly charged system a typical reading should be around 36psig lo side, and 300psig on the hi side, at 2000rpm's and 90 degrees ambient with 60%humidity.. Other temps and humidities are slightly different. If the comp is not running with the system turned on, it may be an electrical problem, or low refrigerant. My best guess without more info would be a loss of sufficient refrigerant to run the system. My reasoning is systems that sit idle for long periods have seals that dry up and lose refrigerant. It is actually better to use the system more, than letting it sit. post more info and we can help more.
Good luck Semper Fi
PS static reading on a full system would be around 90 to 110 psig, static being with the system off and pressures equalized.

 

Prob just low on freon. If it doesn't have the exact amount that makes it happy, it will not cool. The systems is very good about leaking freon from the Schrader valves over time.

 

How long(in seconds) is the compessors on and off cycles when the a/c is on max or set to 60 degrees? You can clearly hear it click on and off.. The compressor should stay on most of the time... When it is low on freon it will cycle on and off from every 3 seconds to 15 seconds depending on how low the freon is.. The temperaure coming out of the vents should be around 40 degrees if its cooling properly

 

I had a similar problem with mine recently. System seemed to be working but the air wasn't cold. It turned out that the belt had come off. I had an underdrive pulley installed a couple weeks before that and the belt they sent turned out to be a little too large. Got a smaller belt on it and it's been great ever since.

 

It is an Automatic Dual Zone.
I cannot hear it click off until I turn it off.
It's only done the "blinky light" thing twice to me. that's when I bought the bottle and charged it. But it still didn't blow cold.
I mentioned the ambient temp because that is what the gauge that came with my bottle reads, but that at least meant that it had 134 in it.
I do have an underdrive pulley, but I had that put on almost three years ago. A/C worked then.
The problem began after moving to the Pacific Northwest and not needing the A/C in a 60 degree summer (Olympic Penninsula, WA)
I've been underway for the past couple of months, but am getting ready to get back home, so I am hopng to get it fixed before I PCS transfer.

 

Have you looked to see if any HVAC codes have been thrown?

 

if memory serves, no. But again, it's been a few months... I'm 90% sure it's no.

 

Here's an interesting one that I'm sure someone will have the answer to. My A/C has been blowing increasingly warmer over the past month or so. Still much cooler than if I shut it off, but nowhere near as cool as it should be. Here's what's odd, the passenger vents blow considerably cooler than the driver's side vents. Still not as cold as when everything was working ideal, but definitely cooler than the other two. Thoughts? Thanks in advance.

 

word of advice: there are two kinds of posts: Reply and New Thread. you choose the wrong kind.

I was going through my laptop last night and I found this interesting program I bought from another forum member. It was a GM stand-alone Service Manual for GM cars/trucks.
It has a step-by-step diagnostic procedure for testing and troubleshooting the a/c system on the vette. This might be useful.
gotta buy a manifold gauge.

 

Hi, From the info you are giving, it is fairly sure that you are undercharged. And the fact that you have an underdrive pulley means that you need to compensate for the less rpm's of the ac unit when charging. What that means is that whatever pressures you are trying to achieve at 2000rpm's on a oem pulley will not be correct on your unit. You may have to go a few hundred rpm's more to achieve the right results. Doing the math ratios comparing your pulley to the oem should get you a better result. And charging at idle with an underdrive pulley will definitely not get the optimum results without compensating the amounts..
Semper FI
To BGDDYKWL, you also need to top up. There are other possibilities, such as an actuator problem on a dual zone system, but from your info, I would check the charge and bring it up to specs.
Below are the specs from the service manual
++++++++++++++++++++++++++++++++++
The below chart assumes testing at idle speed, after the system is on for at least 5 minutes. I personally prefer to use 2000rpm's because from experience I've found you get better results, but the chart below will work fine to.

A/C Performance Table Ambient Air Temperature
Relative Humidity
Service Port Pressure
Maximum Left Center Discharge Air Temperature

Low Side
High Side

13-18°C (55-65°F)--ambient temps
0-100%--Humidity
211-241 kPa (31-35 psi)--lo side
500-740 kPa (73-107 psi)--high side
8°C (46°F)--maxium center vent temp, yours may be lower

19-23°C (66-75°F)
Below 40%
193-223 kPa (28-32 psi)
780-1090 kPa (106-167 psi)
8°C (46°F)

Above 40%
209-239 kPa (30-35 psi)
730-1050 kPa (106-167 psi)
9°C (48°F)

24-29°C (76-85°F)
Below 35%
172-214 kPa (25-31 psi)
1020-1227 kPa (148-178 psi)
9°C (48°F)

35-60%
199-229 kPa (29-33 psi)
970-1300 kPa (141-189 psi)
9°C (48°F)

Above 60%
207-237 kPa (30-34 psi)
1020-1500 kPa (148-218 psi)
10°C (50°F)

30-35°C (86-95°F)
Below 30%
210-240 kPa (31-35 psi)
1130-1520 kPa (164-221 psi)
10°C (50°F)

30-50%
208-238 kPa (30-35 psi)
1190-1670 kPa (173-242 psi)
11°C (52°F)

Above 50%
205-235 kPa (30-35 psi)
1280-1910 kPa (186-277 psi)
11°C (52°F)

36-40°C (96-105°F)
Below 20%
226-256 kPa (33-37 psi)
1280-1650 kPa (186-240 psi)
12°C (54°F)

20-40%
218-248 kPa (32-36 psi)
1360-1870 kPa (197-271 psi)
12°C (54°F)

Above 40%
211-241 kPa (31-35 psi)
1520-2100 kPa (221-305 psi)
12°C (54°F)

41-46°C (106-115°F)
Below 20%
238-268 kPa (35-39 psi)
1460-1830 kPa (212-267 psi)
13°C (55°F)

Above 20%
226-256 kPa (33-37 psi)
1570-2100 kPa (228-306 psi)
13°C (55°F)

47-49°C (116-120°F)
Below 30%
238-268 kPa (35-39 psi)
1750-2090 kPa (254-303 psi)
14°C (57°F)


--------------------------------------------------------------------------------

 

I hope this helps you to,
Becauce i think its some very good info, so im going to print it so i will have it. Thanks. dbiddle

And i was just reading your post ok?.. I did not want you to think i was stealing your info.

Take care and i hope you get it working ok?

 

If the light flashes and then goes out chances are it is freon.

 

You are most likely slightly low on 134. The freon is cooling only the side of the evaporator where the line is coming in at, and there is not enough to cool the whole evap. Driver side is "starving" for freon and will not get cold. Most likely <1 can will fix it. Other possibility is blend doors, but I doubt it.

 

Yeah, I just figured since this thread title is basically the problem I'm having that I'd try here first before starting a new thread as I know on some forums people will sometimes get irritated by seeing like 10 of virtually the same thread.

Thanks for the info.

That has happened over the past couple of months when I first turn the car on and then immediately turn the A/C on (especially when the car was out in the sun), but all I would have to do is press the A/C button a few seconds later and it would turn on. Just figured it was some weird thing when the car got too hot or whatever.

Do you think it would be worth me buying and adding a can myself or should I just take the car in and if that's all it needs have the shop do it? I'm not really a hands on type so any kind of extensive testing with gauges, pressures, leak detection, etc. isn't something I can do. Thanks.

 

got it... my belt slipped off... works like a champ now