89 air cond switch

Doesn't the control have a setting for MAX air and another setting for "NORMAL or Just AC? MAX is the recirc setting.

No Max or Recirc... just AC and OFF...

Hmm, sounds like it might be an aftermarket unit. Some of them look close to factory but not quite. I don't think Chevy has built an AC unit that did not have a recirc setting since the 60's. Is your auto temp control? If so, that might not give you manual control.

My Dad's 90 GMC Sierra is the same way. No max setting. Just A/C on and off. It came this way from the factory.

Bob

Its not aftermarket as Bob stated, it came from the factory that way... I do know the trucks history and it never has been replaced...

Maybe it was controlled by the full COLD setting at of the temp control. It's possible that setting that all the way to cold put it on recirc. You'd be able to tell from the sound of the fan. I know GM used to have a vacuum switch at the full COLD temp position that shut off the hot water flow to the heater core. But they also had a recirc position too on the car I had that was like that (69 Pontiac).

"max" air is re-circ.

If no "max" setting, then moving the temp control all the way to cold will re-circ. Sounds like a dealer added A/C to me.

re-circ. Sounds like a dealer added A/C to me.

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No no... thats the way they came until 93-94. I'm not sure if the trucks have rec. air... AC units have the electronic control pannel, where as the non ac units use the old tryed and true cable pullys. Im not sure, but i think temp control set to full cold puts the system into rec. air mode.

HDS

re-circ. Sounds like a dealer added A/C to me.

Easy enough to test. If it goes into recirc you'll here the extra noise from the fan.

re-circ. Sounds like a dealer added A/C to me.

Putting the setting to full cold, there is no change in the fan at all. My Dad's 90 Sierra came from the factory without a Max or Rec setting. Now my friend's 94 Silverado did have a Max setting. My Dad's unit is not an add in. The truck was purchased in Texas and came from the factory the way it is.

Bob

All I can say is my 87 chevy truck had and my 91 chevy truck has a max air setting, and that straddles your dad's truck production date.. Both of these are Tahoe editions, both manual air, not climate control. Controls are verticle on the right side of the dash. The 93 Aastro van I drove at my last employer was the same way. So dwas my mom's 90 Corsica. and the 88 Celebrity wagon it replaced. Just because you bought the truck new from a dealer does not mean it does not have dealer add on air. Especially in Texas.

Whitelightning

re-circ. Sounds like a dealer added A/C to me.

Any chance of a picture of the control head? I'm sure you are correct, it's just hard to believe GM cheaped out to the point were they actually didn't even include a recirc setting. How do you know it is a factory AC? Was it purchased new with window sticker? I don't know if it still happens but quite a few years ago dealers often made extra profit by ordering vehicles, esp trucks, without AC and then adding it themselves.

It's obvious now, that it was definitely a dealer add on.

re-circ. Sounds like a dealer added A/C to me.

Yes it was purchased new with a window sticker that listed the factory A/C on the sticker. What do you mean by control head? I can take a picture of the dash and the control knobs but I'm not going to take his dash apart.

Bob

Well guys I know what's in the truck and how it was purchased. We will just have to agree to disagree. I know for a fact the window sticker on the truck when new listed factory A/C. And there is no Max setting on the knob nor does the fan speed change when placed on full Cold.

Bob

my ac is NOT add-on... its factory...

also I just found this in the factory owners manual...

AIR CONDITIONING BUTTON To turn on the air conditioner, press the A/C button. The A/C symbol will light in the VF display and the air will be discharged from the dashboard vents with the fan in "LO" position. The system will automatically determine if it needs recirculated or outside air.........

now back to my original post...

Question is can you install the newer switch and get everything to work and if so how many other things need to be changed to make this possible?