The A/C on my 95 is having a problem. When you first get in and turn it on, everything is fine. Blows really cold air. Turn the fan down to 3 or so then try to turn it back up to a higher setting, you can hear the fan motor ramp up, but the air does not make it to the vents......its almost like when I turn it down a damper closes and does not open when I turn it back up,. any ideas on what it could be? I guess if I just left it on high it would work forever. Any advice on where to start would be great.


jeff

 

I'm having a similar problem where it seems to want to primarily blow out the defrost vent regardless of the settings. See if the two threads below might be of help:

http://forums.corvetteforum.com/show....php?t=1514042

http://forums.corvetteforum.com/show....php?t=1840572

 

Thanks for the links. It seems that all of those problems started with the air out of the defrost vents. Mine starts out working fine then goes the other way. And mine is a 95. So, could it be the controller??

thanks,

jeff

 

Oops, saw your avatar and assumed that it was the GS. That collapsing vacuum line problem seems to be a 96 only problem so far. I thought it might be vacuum line related because that's what controls those vents. However, now that I think about it, I guess if it were vacuum line related, the fan speed settings wouldn't matter. Let me take a look at the troubleshooting chart in the 96 FSM (pretty sure the AC is the same 95-96). Do you have the automatic or manual HVAC?

 

The first thing you need to do is get R134 gauge on your high and low side fittings and check your pressures with the engine on, AC running. The high side pressure is going to be ~200psi and the low side ~50psi. Also, see if your compressor stays on constantly. If you have a proper charge in your system, your compressor should cycle on and off periodically. If your compressor clutch is constantly engaged, yes you could be low on refridgerant, and this can cause your evaporator to freeze up.

Also, I am a little confused as to your problem. Are you saying that the cold air turns warm after awhile, or that the volume of air coming through your ducts is reduced(reduction in blower motor speed) ?????

 

the air remains cold. when I turn the fan speed down, then after a while try to speed it back up, you can hear the fan ramping up....but the air does not make it out of the vents. Its like a damper door is closet off. if you leave the car awhile and try it again, it blows fine again. the blower motor speeds up, I am just not getting the air through the vents at that rate.

 

If fan speed goes back up on demand, the air then has to be going somewhere. Can you tell if the ducts are splittin' the flow up somehow?

What happens if you manipulate the duct controls?

Get Mr suncr on it...

 

The fan is going back up, the passenger is saying that it is throwing more out there feet. I'm not feeling anymore on my feet. I am trying to get it to duplicate the problem in my driveway.....so far not having any luck getting it to do it again. And this is NOT a new only once thing, I have just not been driving the car so I have been able to ignore the problem.

 

The problem is that its 106-107 degrees around here and your flux capacitor has melted. Its either that, your muffler timing or a witch has hexed you. Brian.

 

Is your fan control 'Off, low, med, high'? Or push a button, 0 -10?

 

So, you do not have an AC issue. You have a diverter problem.

Right?

 

Right.

 

I just replaced the flux capacitor, and bumped up the muffler timing. And if you read my entire post you would have known that this has been happening, not just with the 100+ weather.......but I dident think about a possible whtch hex. hmmmm

jeff

 

Strange, but this sounds like a Programmer problem which controls where the air flows by sending vacuum to any of the three solenoids that move the HVAC doors and one of yours is getting particularly lazy when the blower speed is reduced. Given it's intermittent nature, troubleshooting is going to be a crapshoot, but I'd start at the source and verify that the check valve and lines are intact and that the vacuum tank is capable of holding 10 inches of vacuum. I would also, if you can get this duplicated in your garage, verify that the blower is giving it all it's got by checking for 12 volts at the connector; or jumpering it directly to the battery. Or, when it's working right, aiming a hair dryer at the blower module and see if the problem is duplicated with heat. Assuming all of this checks out, you're going to need to examine the vacuum harness at the Programmer and test each solenoid to make sure that they are capable of holding a vacuum. You might also consider letting a dealership take a stab at it with a bi-directional scanner as that will bypass the Controls and rule out a problem with the serial data lines or the Controls. Finally, before you give up and simply spend your dough on a new Programmer, you might just try to clear it's memory by disconnecting and reconnecting the battery.

 

sounds like the controller. Under the dash.
Give one of these a try first part 10135692 or AC 15-5421