It's not in the manual . I discovered it purely by accident . I suspect the engineers think it's to our benefit to have A/C cycling on when we DON'T want it to minimize situations that could fog up the interior ( such as humid but not hot weather) and figure we are too stupid to push the A/C or defrost button in that case.

 

I tried this and it does not work on my car. No matter how fast I press that mode button twice it just ends up changing the mode. Turn the climate off and then back on, AC comes back on.


[Modified by rbartick, 12:34 PM 4/8/2002]

 

I can't believe I have missed this post for so long (okay, I don't have a Z06). The auto climate control is far and away my biggest complaint with the C5. You can overide the compressor and get it where you want it, but it is seriously difficult to do. This is without a doubt the most un-user-friendly system ever put in a car, and I've had many cars with auto climate control.

Please Corvette Engineers. Do your homework on other systems and change it. I have an Infiniti now that is very easy to set how I want it. In fact, it has an "economy" mode just for those instances when you don't want the compressor coming on at all. Like, say, when it is 35 degrees out and all you want is the heater on (I've had this set in the Corvette and the compressor came on)

 

I'd be happy with the 60s style slide rod for opening the vent. It's simply jerky that you would have to play "tricks" with a AC system on a sports car. Get real. Oh well, at least the defrost works well, that didn't in my cars from the 70s, 80s .

 

The way the climate control system works is: whatever button you dont push... the computer thinks it can control... so if you dont hit "blow speed" up/down... the computer will control blower speed for you as you adjust temp or as outside temp changes. If you dont hit "mode", the computer may change it to the defrost mode - which will turn on the AC... even you just just shut off the AC, 2 seconds ago.

So, as stated above: if you hit the blower speed, AC off, and then hit mode... yes, the AC will not come on... for that trip. And for some reason, hitting mode once does not change the mode, you have to hit it twice or three times, etc... slow, fast, whatever. But as soon you turn the system off, and back on the AC is on again.

Unless you have figured out a way to really lock out the AC forever... in that case, it does not work in my car either... just tried it.

 

The only "solution" I came up with is to leave the climate control on all the time. If climate control is on and the AC is off (in a non-AC required air delivery mode) when I turn off the car then the climate controls will come on without AC the next time I start. I would not call this an acceptable solution.


[Modified by rbartick, 10:30 PM 4/8/2002]

 

Hmmm. my car's a '97 . Unfortunately, the engineers probably found this " bug" and " corrected " it in later model years. Any other '97 owners want to confirm this method works , even after turning off / restarting engine ?

 

Why?

If it hurts banging your head against the wall, stop banging your head against the wall.

 

Tried usroute66 MKW's "double mode" trick yesterday and it worked great on my 2002. I'm pretty happy with this as a solution because most of my Z06 miles are highway miles and I will not need the defrost or the A/C much except in the summer. Thanks

Agree with you 2ndVette, it would be nice to have a way to permit airflow into the cabin without having to pump it with a fan. With enough air speed at cruise, there is really no need to run a fan to get fresh air. Are you listening GM? We are smart enough to hit the auto function when we need defrost.

 

>Tried usroute66 MKW's "double mode" trick yesterday
>and it worked great on my 2002

Turn your climate controls completely off (while in floorboard or vent mode), and then turn it back on by pressing the fan or mode button. Does the A/C stay off? Turn off the climate controls, turn off the car, restart the car, and turn the climate controls back on. AC still off?

If I try the "double mode" method in my 2002 while it is in floorboard heat mode it just ends up changing the mode. I tried it while my mode was not in auto mode. I turned on the fan, manually changed the mode to floorboard, turned off the A/C compressor, and then hit mode twice. This just changed my mode.




[Modified by rbartick, 11:03 AM 4/9/2002]

 

Here's an "off the wall" explanation of why the controller cycles the compressor on with any activation of the ECS (environmental control system).

I'll start with a reminder of how the MANUAL controller was set up in the "old days".
Far left with the control lever was "OFF"
Next position was "AC".
Next was "MAX AC"

Then there was something like: VENT,HEAT,DEFROST,DEFOG
Something like this anyway.

Every time you asked for HEAT or VENT or ANYTHING besides AC or MAX AC you went through the settings for AC and MAX AC.
This cycled the compressor clutch on at least for small time the lever went through the AC and MAX AC position.
The question is "why would the engineers do this".
My off the wall answer is to ascertain the compressor clutch seals always got a new "dispensment" for lack of a better word from the lubricant (refrigerant lubricant) in the sealed system.
They may have determined, way back when, that the seals would fail to function properly if the compressor shaft was allowed to just sit in one spot too long.
How many times have you not used your AC for a period of months to find that the darn thing won't work NOW because it's low on freon?
Period cycling of the compressor will most likely stop this. Or at least helps the seals to remain pliable in a not so friendly environment under the hood of our cars.

Sounds like the General is doing the same thing here with the C5 ECS controller.

See, I TOLD you it was an "off the wall" answer.

Jim Alford
Universal Refrigerant Certification . . . among other things.

 

"Turn your climate controls completely off (while in floorboard or vent mode), and then turn it back on by pressing the fan or mode button. Does the A/C stay off? Turn off the climate controls, turn off the car, restart the car, and turn the climate controls back on. AC still off?

If I try the "double mode" method in my 2002 while it is in floorboard heat mode it just ends up changing the mode. I tried it while my mode was not in auto mode. I turned on the fan, manually changed the mode to floorboard, turned off the A/C compressor, and then hit mode twice. This just changed my mode."


OK, I believe you. I guess the "double mode" method doesn't work under these conditions. I'm still glad to have some control.

I'll try what you suggest, just to learn more about how the system behaves.

Thanks for the info. :cheers:

 

rbartick,

I tried just what usroute66 MKW suggested:

"Here's how to " lock out" the A/C compressor: set your desired fan speed and air flow , push A/C button OFF , the hit MODE button twice, quickly. You're done! Changing the TEMP setting doesn't default it, either. To resume ususal irritating mode, just push AUTO again."

I set the fan speed to the slowest speed, set the air flow to bi-level (it was already showing a fresh air, not recirculate setting), pushed the A/C button OFF, A/C light goes off, and before it can re-light, hit the MODE button twice. A/C stayed off.

If I remember correctly, I had to reset the mode to bi-level, but the A/C did not come back on. I know I adjusted the fan speed again and the A/C continued to stay off.

After about 30 minutes, I hit the AUTO button and the system returned to normal A/C on operation.

Hope this techninque can be of some benefit to you, because you should get some return for starting this cool thread. :cool: :cheers:

 

Yarddog,

Thanks for the response, but I think you may have missed my point. After doing your procedure hit the OFF button and turn everything off. Try to turn the climate back on without getting the AC compressor indicator. I can lockout the compressor if I leave the system on, but if I turn it completely off the compressor will come back when I turn it back on.


[Modified by rbartick, 11:11 PM 4/10/2002]

 

Agreed!

I've been thinking about longish trips in cool weather when we want to leave the heat on, but want the A/C off.

In other situations, you are right...we don't have the control we would prefer.