Switch in temp control

I went out in this heat wave today to get a few things. When I left the house, it wasn't too bad, but in the timespan of an hour it got muggy. Muggy enough that I kicked on the AC. First time this year. In my 95 Grand Prix.

Anyway, it wasn't working that well, and I though I was going to have to get a can of dye and start checking for leaks. Then I realized my temperature control wasn't solid off. As you turn it hot to cold, at the very coldest there's a detent that feels like it's activating a switch. Once I set it there, cold air flooded the car.

I'm pretty sure the AC was working even when the temp wasn't full cold, as it was making the car comfortable and it was obviously drying it out.

But my question is, what is that switch/detent for in the control? MAYBE it was just that I wasn't full cold and it was 'mixing' hot and cold like on rainy fall days when you run the AC more as a dehumidifier, but it sure felt like a massive change when I moved it today.

Reply to
Mike Y
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There is usually a Max(imum) cooling position on air conditioners. I suspect this is what you activated. Compressor runs, more or less, full time. If you run with it this way too long, your evaporator core might just ice up and you could lose cooling until it melts.

Reply to
HLS

Actually, I have a separate "MAX" position. When in that position, the evaporator draws air from the passenger compartment that is already cooled and dried.

I was wondering if when the temp knob is in the full cool position it does something that would keep hot coolant from even coming into the passenger compartment. Is there a solenoid valve in the radiator hoses?

There is nothing in the manual about it.

Reply to
Mike Y

Dont know for sure on your application. On mine, that switch puts the compressor on, almost, full time.. There ARE safety switches that will cause the compressor to disengage, but it doesnt cycle the same was as it does on the other setting.

Reply to
HLS

Don't have the manual for your machine. Looked in the manual for a '94 Oldsmobile Cutlass/Buick Century. There are no switches associated with the temperature lever in these vehicles. I suspect that the detent you are feeling is the resistance of the temperature control door fully closing at the cold end of the lever's travel.

Reply to
Silver Surfer

Ok, maybe. But I have to say that the temp control feels like nothing is attached to it at all. Like it's a VERY free-turning potentiometer... With an 'off' switch at full CCW.

Hmm, maybe it is!

Mike

Reply to
Mike Y

Upon reflection, I began to suspect the same. Just a little opening or cloture of those divertor doors can make a big difference. Easier to comment if we were there, I guess.

Reply to
HLS

Well, I didn't pull the thing out, but it appears there's nothing but WIRES attached to the module. One of these days it will bother me enough that I'll have to pop it out just to see.

Right now I have another issue with the car...

Reply to
Mike Y

Now I'm guessing that you have one of those electronic automatic temperature controls in your machine instead of the sliding lever that manually positions the temperature door. Maybe it does have a potentiometer to set the temperature. The automatic control in my 2002 Oldsmobiles uses up and down push buttons, but the passenger side control is a round knob on the passenger door armrest.

Sure wish I had a service manual for that vintage vehicle. It's making me curious as to what they might be doing with a switch at the cold end of the temperature controller.

I take it from your other post that your butt is dragging the ground.

Reply to
Silver Surfer

Well, yes...

And more on one side than the other. I still have 'spring' action but not very much.

Reply to
Mike Y

What you have is the standard electronic control board for the HVAC system. Probably a relative to the ones used in the Malibu.

Something like this?

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Reply to
Steve W.

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Yep, pretty close. I only have 2 buttons, not 4. And I have more functions on the rightmost knob. But even the shape of the knobs look the same.

Reply to
Mike Y

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