1998 AC adjustment?

[XLR8]

Is there an adjustment which can be made to the AC in my C5?

Here's the deal: my AC in auto mode, with the thermostat at its lowest setting (60 degrees) = cold air, blowing 90 mph (sort of an exaggeration but you catch my drift) recirculation showing interior recirc only.

Then: if I turn the thermostat up 1 degree to 61, the AC almost completely cuts off, can barely feel any air and only if I place my hand directly in front of the middle vent. The recirc light also switches itself to indicate OUTSIDE air is being drawn in. I have to manually switch it back to interior recirc, the humid summers here mean you don't want ANY air coming in from outside.

No work done on the AC lately. In the last 2 or 3 years I've had an actuator in the dash replaced after it failed and I replaced my head unit when the LCD went too dark to read the settings.

Any ideas or suggestions? I can't leave it on full blast all the time but even a 1 degree difference is unbearable.

Jane Ann

 

[fixvet]

I can't help you specifically with your question, but does it work okay when you change it to a regular mode........not AUTO? If it does, leave it there and adjust the fan and recir. button manually. I also have the AUTO feature, but never use it. I set my temp to 68deg and leave it alone. The sensors will still allow cooled or heated air into the cabin automatically to mantain that temp. I usually have my fan set to the second hash mark on the screen.

Good luck

 

[gmjunkie]

Pull the codes Jane Ann!! :L I'm not as sharp as Paul on these cars,But sometimes I get Lucky!!!

Pulling Codes on a C5

 

[XLR8]

Thanks for the suggestions guys.

I've haven't tried running it in manual, but I will give it a try. The thing is, in the past I've always used auto with no problems... If manual works I'll just stick with that. Thanks!

Jesse, I'll try to pull the codes this weekend and post them here.

And don't sell yourself short, you've helped me and many others time and again and we appreciate it too!

Matter of fact... this is one time I can help you... check my cruise control thread for a "fix" someone suggested I try and it worked!

Jane Ann

 

[fixvet]

Sooooooo Jane Ann.......what's the verdict on your a/c issues? Iquiring minds want to know! Did you try the manual settings?

 

[XLR8]

Sooooooo Jane Ann.......what's the verdict on your a/c issues? Iquiring minds want to know! Did you try the manual settings?

Yep, I did. The manual settings seem to work better. It doesn't drop off as low in manual as opposed to auto when I adjust the temperature.

BUT... something still puzzles me. When I adjust temp setting from 60 degrees to 61 degrees, it still switches to outside air.

I've set it back to inside air only and even tried resetting the #1 memory button on the door by holding it down AFTER switching it back to inside. But the next time I cycle through the steps again, it goes right back to drawing in outside air.

 

[fixvet]

Where do you have the "mode" button set? The one below the "Auto" button. Be sure it's set to the symbol with the arrow pointing to the upper part of the interior(like for vent or bi-level), not defrost or anything else. It seems I once ran into something like you've described because I didn't have the symbol in the correct setting for just the a/c to work properly. It was like it wanted to override what I wanted. I thought it was all very weird, but the controls seems to work for certain things only if everything is set correctly too. I just figured it was smarter than me, and left it alone once I played around with it long enough for it to make me happy! Experiment with the different settings, when you have the a/c button lit up.

Good luck!

 

[XLR8]

Where do you have the "mode" button set? The one below the "Auto" button. Be sure it's set to the symbol with the arrow pointing to the upper part of the interior(like for vent or bi-level), not defrost or anything else. It seems I once ran into something like you've described because I didn't have the symbol in the correct setting for just the a/c to work properly. It was like it wanted to override what I wanted. I thought it was all very weird, but the controls seems to work for certain things only if everything is set correctly too. I just figured it was smarter than me, and left it alone once I played around with it long enough for it to make me happy! Experiment with the different settings, when you have the a/c button lit up.

Good luck!

I checked that, thanks! The arrow points mid-body as you describe.

It's a minor quirk I can live with because at least I 've got more control this way. Maybe one day I'll stumble across a reason for it, maybe not. But, as I said, I can live with it and I appreciate your suggestions and time.

Jane Ann

 

[BigJimZ16]

I would think that the cabin temperature sensor is faulty... I'm assuming that there is one. If the sensor tells the auto control that it is already colder than 61 deg. it will do exactly as you describe.

 

[XLR8]

Good point, Jim, but wouldn't it do the same thing in either auto or manual operation? Because in auto, a change from 60 to 61 decreases air flow dramatically, but in manual, the difference is less noticeable.

Or does the temp sensor only come into play in auto?

Jane Ann

 

[BigJimZ16]

Good point, Jim, but wouldn't it do the same thing in either auto or manual operation? Because in auto, a change from 60 to 61 decreases air flow dramatically, but in manual, the difference is less noticeable.

Or does the temp sensor only come into play in auto?

Jane Ann

The whole point of "Auto" is closed loop control. It maintains what ever temperature you select. In manual, the feedback is the hair on your arm... when it stands up, it's too cold! I would be interested to know what happens if a hot temperature is selected in Auto. If the sensor is indeed dead, the system should do the opposite which would be to roast you out at full blast because the feedback says that it is still cold.

 

[fixvet]

The whole point of "Auto" is closed loop control. It maintains what ever temperature you select. In manual, the feedback is the hair on your arm... when it stands up, it's too cold! I would be interested to know what happens if a hot temperature is selected in Auto. If the sensor is indeed dead, the system should do the opposite which would be to roast you out at full blast because the feedback says that it is still cold.

Unless I've misunderstood you, I'm not sure I agree with you about the temp. selection in the manual mode. In my old '98 it doesn't matter if I select Auto or Manual, the temp knob temp setting is what the system trys to maintain. It's just that in manual the fan speed will never change, whereas in Auto the fan will automatically run faster at first if you select a low temp reading, and will shift from recir. air to outside air when needed too. That's why I prefer the manual mode so the fan speed is constant on the 2nd or 3rd bar fan reading unless I want to change it. In my car in Auto with the temp set to 60deg, the fan runs full blast automatically at engine start up until the a/c drops the temp in the summer then it begins to slow to the lower speed or speeds as needed. If it's really hot in car, this may take quite awhile......listening to the high speed fan noise too. The same goes for the heater on Auto setting in the winter. Normally, I set my temp to 68 and leave it with the a/c button on. When it's really humid outside, I leave it in the recir.air setting to keep out as much humidity as possible, which makes the cabin much colder. In the winter here, I just leave the a/c off and still use the vented air instead of the heated vents down below. I like the cabin air to be circulated up top, not at my feet, plus.....I guess I'm just a control freak, eh?? :L:L:L

Good luck