AC Logic?

Jourden · 11-18-02, 09:36 AM

Does anyone have the logic behind the functions of the AC?

I am sometimes baffled as to why the AC insists on being on when all I am wanting to do is turn on the fan. For instance, this morning, it was 46 outside and I wanted warm air (not recirculated and set to 76 degrees) to be driven by the fan. The AC light was on and each time I tried to turn it off, it just blinked at me and stayed on.

And why does the AC come on every time I turn on the fan? Sometimes, I want just the fan by itself and to do that I have to turn on the fan and then turn off the AC. As described above, there are times when I go to turn the AC off while the fan is running and it will turn off. Then, there are times when it just blinks at me and stays on.

Not a big deal but, I sure would like to know the logic behind this.

MsSchroder · 11-18-02, 09:51 AM

Are you talking about your 2003? if so, this happened to me also. It turns out, if you have it on any kind of defrosting or defogging setting, it will do this. Make sure you don't have the front or rear defroster buttons pressed. Then, press the MODE button and make sure it does not have a defroster icon.
After I did this, the a/c did not come on.
Tammy

Jourden · 11-18-02, 10:06 AM

Yep, the 2003. I will check what you have said to be sure.

Kinda funny, the '65 has no buttons! ...'cept for the radio...

Thanks!

MsSchroder · 11-18-02, 10:33 AM

does it have the dual climate control option (you can tell if there are 2 knobs, 1 for driver, and 1 to adjust the passenger climate controls)? if you do, then having it in AUTO mode might turn on the defogger also (or so the manual says).

Ctfoodguy2000 · 11-18-02, 10:49 AM

Exact same on my '02. It is in owners manual.

MsSchroder · 12-03-02, 07:40 PM

Now I'm confused about this. I drove it this morning when it was in the 40's or 50's, and the dang A/C was on... and there was no defogging or defrosting going on that I could see.
(this is the dual climate control system)
It looked like it was in automatic mode... I tried switching it to manual. Then I shut off the a/c. It went off, but soon thereafter it came on again.
Eventually I got it to go off by fiddling with it but I'm not sure how.

I'm curious if you ever got this straightened out, Jourden.

12-03-02, 08:16 PM

I too am still trying to figure out the logic on my '97 A/C. So far it's been hit or miss. I guess it might do me some good to read the owners manual......

But I might get better NFO from this forum and it's a lot more fun!

MsSchroder · 12-03-02, 08:38 PM

Well I've just gone back to the owners manual, again, and I still don't get why the A/C kept coming on today.

The manual says that when it is in AUTO mode then "AUTO" and the outside temp will appear on the display. (It did not say AUTO for me). It says you can change it to manual mode basically by :
- pressing the fan speed button
- pressing the MODE button
- pressing the A/C button to turn off the A/C

it also says that "the air conditioning cannot be turned off in defrost and defog, as it helps to remove moisture from the vehicle. It also helps to keep the windows clear"

Darn, I'm just going to have to drive it again tomorrow to get to the bottom of this

only in the interest of furthering my knowledge, of course

12-03-02, 08:42 PM

Tamara,

which is BTW my wife's name...

When you figure out how this A/C logic works and can put it in simpler layman terms than what the manual can, please let us know. In the meantime I will just keep fiddlin' with the knobs until it gets close to what I want it to do.....

MsSchroder · 12-03-02, 08:48 PM

Quote:

Originally posted by 97moneypit
Tamara,

which is BTW my wife's name...

When you figure out how this A/C logic works and can put it in simpler layman terms than what the manual can, please let us know. In the meantime I will just keep fiddlin' with the knobs until it gets close to what I want it to do.....

Do you call her Tamara or Tammy? I've gone by Tammy most of my life but I had this friend once who had a big hang-up with it... he refused to introduce me to his friends as anything but "Tamara".... guess he thought Tammy sounded too rural...:s well come to think of it, I guess that's true..

Anyway, I'll let you know about the a/c. I plan to conduct an extensive study tomorrow. Perhaps I'll even start tonight.
My husband's .02 worth is this:
"The a/c is running most of the time. It runs most of the time on most settings on my truck". so there you have it

MsSchroder · 12-06-02, 05:12 PM

Here's my observations of the a/c logic on a 44 degree day. I had the inside temp set at 73. I don't know if it matters, but I have the memory package.

the a/c will be on if the setting is "auto". Also note: the "auto" button is not a toggle; it only turns "auto" ON. You have to change to manual mode by the 3 methods I posted previously.
the a/c will be on if you have any defog or defrost setting on
the a/c will be on if you have air set to recirculate

In all of the above cases, the a/c light will just flash at you if you try to turn it off.

the a/c will remain on if you switch it from an automatic mode to a manual mode, or if you switch from recirc to fresh air. To turn it off you have to press the a/c button. (Even so, it came back on once; I had to press a/c again and it stayed off)

Conclusion: I think the only way you're going to avoid having the a/c compressor running is to have fresh air, no defog or defrost, and manual mode.