Kaitsu
Well-Known Member
I´ll provide pics of it from shop manual. There is the front control panel setup drawing and its like the one you posted, however, instead of word "temperature", there is Fahrenheit scale from 65 to 85 F.
MoPar Bracket for 100 amp alternator and A/C
- Thread starter Kaitsu
- Start date
- Status
Jack Meoff
Mopar Maniac
That sounds like the newer ATC style.
Jack Meoff
Mopar Maniac
That's what's in yours now?
Last edited:
Kaitsu
Well-Known Member
I broke my scanner, cannot take a picture of the assembly from the books. So, mine is like you showed separated from vehicle a few messages earlier, its the Manual AC. However, in the books also includes the one you sent in your last message. (S)ATC is an option for Diplomat, Caravelle, St. Regis, LeBaron, Gran Fury, Cordoba, Newport, New Yorker and Mirada. Not Aspen or Volaré. I was wondering if it wouldn´t work or fit in an F-body at all.
Jack Meoff
Mopar Maniac
ATC has a dash mounted sensor and an electronically/vacuum controlled blend door if memory serves..... The old style like the one in your Aspen is a cable controlled blend door with vacuum controlled switching.
I'd have to dig through my manuals....
I'd have to dig through my manuals....
Kaitsu
Well-Known Member
So, if I got it right, ATC is a microprocessor controlled unit that gets "clues" about the comfortable temperature from: 1 bi-metal sensor on dash, 1 bi-metal sensor from ambient (outdoors), and the selector on control panel. These 3 make the processor to decide how to air is blended on the ducts.
IE: Driver wants a comfortable 75 Fahrenheits (It´s winter here close to arctic circle). He turns the selector to 75F. The MP (microprocessor) starts to pull cables to make the inside air as hot as possible. When the sensor on dash starts to expand, it tells the MP that its about 75 now, hold the pure hot air. Now MP starts making a blend that keeps that temperature. The outside temperature sensor keeps updating MP that "its freezing my ass out here don´t give so much cold air in blend" and therefore wont charge the AC compressor so much.
Please correct me if there was a false claim in my explanation.
IE: Driver wants a comfortable 75 Fahrenheits (It´s winter here close to arctic circle). He turns the selector to 75F. The MP (microprocessor) starts to pull cables to make the inside air as hot as possible. When the sensor on dash starts to expand, it tells the MP that its about 75 now, hold the pure hot air. Now MP starts making a blend that keeps that temperature. The outside temperature sensor keeps updating MP that "its freezing my ass out here don´t give so much cold air in blend" and therefore wont charge the AC compressor so much.
Please correct me if there was a false claim in my explanation.
Jack Meoff
Mopar Maniac
You're very close.....but as far as I know there's only one internal cabin sensor.
I'm pretty sure you have the old style temp control and you'd probably be best to stick with that. The unit I posted is actually for sale if you need one
I'm pretty sure you have the old style temp control and you'd probably be best to stick with that. The unit I posted is actually for sale if you need one
kkritsilas
Well-Known Member
My 1980 Cordoba and 1982 Mirada both have the automatic/semi-automatic temperature controlled AC. Both units look a lot like the one's in Captain Caravelle's picture in post 43, except that the push buttons on mine are chrome. It may be that the one's in Captain Caravelle's pictures are also chrome, but the lighting makes them look black.
Kostas
Kostas
Jack Meoff
Mopar Maniac
The pic in post #43 is from my 87 Fifth and yes they're chrome.
I guess they were using ATC in J bodies by then??
All I do know for sure is my 80 Volare is the old style like the previous pictures I posted.
kkritsilas
Well-Known Member
My 1981 CMX has the full manual air conditioning, no temperature slider. From the manual I got with my 1980 Cordoba, it seems like both were available, the manual AC, and from the way thait it is described in the manual, the higher level (and I assume more expensive) Semi-Automatic Temperature control.
Kostas
Kostas
Kaitsu
Well-Known Member
Thanks for replies. Good to hear that kkritsilas´s Corby could´ve got SATC. My Aspen already has manual AC, so I was considering if one could simply swap the control panel for SATC one, then buy off an used set of wiring, sensors and plumbing and start choosing his own temperature. Need to confirm about the blend air system from the manual.
kkritsilas
Well-Known Member
Kaitsu:
Another point you may want for reference purposes: There is probably no microprocessor in the ATC. It is probably a bi-metallic strip or possibly a thermistor with some analog circuitry behind it. There are very few cars that had any microprocessors in the days our cars were made. It is possible that the ESA/Lean-Burn system had one, but it is just as possible that it was just a bunch of "glue logic". The fuel injection and digital dash of the J/Y body Imperials most likely were the first ones used in Chryslers. As a car manufacturer, Chrysler could get volumes of thermistors with the correct, consistent temperature curves, and the analog circuits to do the temperature control would be almost trivial with an analog circuit. The analog circuits could then be used to power a solenoid, or switch vacuum to move the air blend door.
There is no need for an external temperature sensing element, as it really doesn't matter what the external temperature was, as long as the cabin was at the correct temperature.
Kostas
Another point you may want for reference purposes: There is probably no microprocessor in the ATC. It is probably a bi-metallic strip or possibly a thermistor with some analog circuitry behind it. There are very few cars that had any microprocessors in the days our cars were made. It is possible that the ESA/Lean-Burn system had one, but it is just as possible that it was just a bunch of "glue logic". The fuel injection and digital dash of the J/Y body Imperials most likely were the first ones used in Chryslers. As a car manufacturer, Chrysler could get volumes of thermistors with the correct, consistent temperature curves, and the analog circuits to do the temperature control would be almost trivial with an analog circuit. The analog circuits could then be used to power a solenoid, or switch vacuum to move the air blend door.
There is no need for an external temperature sensing element, as it really doesn't matter what the external temperature was, as long as the cabin was at the correct temperature.
Kostas
Kaitsu
Well-Known Member
Thanks for clearing this for me. After I get my scanner to work I´ll get photos of the assembly from parts catalog and the info on shop manual.
Kaitsu
Well-Known Member
kkritsilas
Well-Known Member
I think the system is called semi-automatic because you manually have to use the pushbuttons to set the mode; in modern automatic temperature controlled air conditioning systmes, the temperature set point and the cabin air temperature determine if the system is heating or cooling. With the semi-automatic system in our cars, it cannot go from heating to cooling; you must put the system into heating or cooling mode, and the slider determines when it needs to allow more heat or more cooling.
Kostas
Kostas
Kaitsu
Well-Known Member
That´s what I didn´t got: what happens when you´re in hot weather and select Heat but turn the temperature down to 65F. Shouldn´t the system go crazy or does it understand not to confuse and still blow like it should to make the correct temperature?
Jack Meoff
Mopar Maniac
When you turn the temperature down you're closing the blend door.
That lever is attached to a cable that opens and closes the door.
That lever is attached to a cable that opens and closes the door.
kkritsilas
Well-Known Member
I think what happens is this:
a. In heat mode, when the temperature sensor detects the cabin temperature is below the slider setting, it moves the blend door to allow more heat in, at the fan speed selected by the fan speed slider. As soon as that temperature is reached, the blend door closes, not allowing any more heating.
b. In AC mode, if the temperature sensor detects that the cabin temperature is above the slider setting, it moves the blend door to allow cool air from the AC in. As soon as the cabin temperature is at the same temperture as the slider setting, it closes the blend door.
What the system cannot do, is heat the cabin when the system is in AC mode, or cool the cabin when it is in HEAT mode. It also cannot control the fan speed. Modern automatic temperature controlled AC can heat, cool, and in many cases, speed up or slow down the fan(s).
I don't think the lever in the semiautocmatic AC is directly connected to the blend door, or the system would never be able to shut off the heat or air. Instead, there is something like a balanced bridge circuit, with the thermistor or bimetallic strip as one leg of the balanced bridge. When the thermistor resistance value changes due to the temperature, it generates a voltage (due to the bridge now being unbalanced) that is amplified and either electrically moves the door, or moves a vacuum valve that moves the blend door. The mode switches on the panel (HEAT, AC) just switch either which blend door gets moved, or the direction the blend door is moved. I don't know if there is one blend door or two.
I can't figure out if the Semi-Automatic system actually can turn the AC on or off, or just moves the blend door. I would need to look at the manuals for that, and I don't have them yet. It may only control the blend door, or may actually turn the compresson on and off.
Kostas
a. In heat mode, when the temperature sensor detects the cabin temperature is below the slider setting, it moves the blend door to allow more heat in, at the fan speed selected by the fan speed slider. As soon as that temperature is reached, the blend door closes, not allowing any more heating.
b. In AC mode, if the temperature sensor detects that the cabin temperature is above the slider setting, it moves the blend door to allow cool air from the AC in. As soon as the cabin temperature is at the same temperture as the slider setting, it closes the blend door.
What the system cannot do, is heat the cabin when the system is in AC mode, or cool the cabin when it is in HEAT mode. It also cannot control the fan speed. Modern automatic temperature controlled AC can heat, cool, and in many cases, speed up or slow down the fan(s).
I don't think the lever in the semiautocmatic AC is directly connected to the blend door, or the system would never be able to shut off the heat or air. Instead, there is something like a balanced bridge circuit, with the thermistor or bimetallic strip as one leg of the balanced bridge. When the thermistor resistance value changes due to the temperature, it generates a voltage (due to the bridge now being unbalanced) that is amplified and either electrically moves the door, or moves a vacuum valve that moves the blend door. The mode switches on the panel (HEAT, AC) just switch either which blend door gets moved, or the direction the blend door is moved. I don't know if there is one blend door or two.
I can't figure out if the Semi-Automatic system actually can turn the AC on or off, or just moves the blend door. I would need to look at the manuals for that, and I don't have them yet. It may only control the blend door, or may actually turn the compresson on and off.
Kostas
Last edited:
Jack Meoff
Mopar Maniac
Not 100% myself.
I was under the impression that the old style blend door was cable operated and the newer ATC has the resistor and motor operated blend door.
If I move my temp setting on the Volare or Caravelle it sure feels mechanical and immediate as opposed to the Fifth where there's a delay and you can hear a motor driving the door.
I was under the impression that the old style blend door was cable operated and the newer ATC has the resistor and motor operated blend door.
If I move my temp setting on the Volare or Caravelle it sure feels mechanical and immediate as opposed to the Fifth where there's a delay and you can hear a motor driving the door.
- Status
