AutoTemp II - where do I begin?

imperigal

imperigal

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Happy Sunday! It's a super hot and humid day here today, which got me thinking about the 73 T&C's A/C system. It's AutoTemp II...and wow does it look complicated. I'm not well-versed in all things AC, but am hoping that you can steer me in the right direction.

I know I will not be using R12. It will be either R143a or Duracool. I will not be upgrading the compressor and condenser at this time.

I haven't even checked yet to see if the compressor turns on/clutch engages. I'm sure there are threads on AT2 overall that would give me much needed insight, but I can't find them.

I do have the FSM, but I guess what I'm looking for is if there have been discoveries made by other FCBO peeps that will make this process easier. Any guidance?

Thanks in advance!
 
Haven't looked, but there could well be one of the Chrysler MasterTech videos on ATII on either www.mymopar.com or in the back of www.imperialclub.com websites. The same "courses" the dealer tech's had to look at. Not sure what model year it might be in, though. Generally, an overview of how things worked, sensors, actuators, operations, and such.

CBODY67
 
Commando is right, read everything you can find and learn the way the system operates BEFORE attempting to anything. These systems were better than the first gen ATC, but they were still a PIA. You can check your compressor simply by putting a socket on the bolt that holds the clutch onto the compressor. With the key off, try to turn the compressor several rotations, if it turns freely, the compressor is probably still ok. You will need to have somebody who knows what they are doing evacuate the system and remove all of the old oil and refrigerant. If this system has not been used for an extended period of time, the filter dryer should be replaced and the front shaft seal on the compressor should be replaced as well. If you are not going to use R-12, be advised that both R-134a and Duracool are less dense refrigerants that what the system was designed for, that means that both of the refrigerants will tend to leak out more readily than R-12. If using R134a, all of the o-rings in the system should be replaced with the modern green colored ones. Consideration should be given to replacing all of the rubber hoses as well as the R134a tends to want to leak thru the rubber tubing and around the various fitting clamps. If that level of expense is not in your budget, just be sure to have the charge checked each spring before using the system. Converted R-12 systems are prone to burning out the compressors if refrigerant pressures drop as this causes the oil in the system to stop circulating and kill the compressor.

Duracool is a simpler conversion, it does not require any modification to the system. Be advised though that Duracool is highly flammable so it should not be used in any system that leaks as a resulting fire could burn up your classic and maybe your garage as well. Duracool as a blend of several hydrocarbon gasses, Propane and Butane and several others.

Once the system has been leak checked and recharged with oil and your choice of refrigerants, you can then start the process of diagnosing system controls. Also be advised that most parts for the control system are obsolete and hard to come by, so figure on spending some time at a wrecking yard or obsolete parts suppliers.

Dave
 
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When I fixed mine, I started by making sure that I could hold a charge and run the compressor by jumping +12v to it. After I had spent lots of money there (replaced all the seals, the compressor, the drier, the ETR valve with an EPR valve and converted to R134a), then I addressed the non-working control system.
 
The control system is actually pretty simple if you understand electronics somewhat. It’s all about maintaining equilibrium. The place to go for help and parts is Performance Analysis Co..
George Murphy can help you determine what you need, which is most likely a servo and/or amplifier. I needed both and also had corrosion at the amplifier connector and replaced all the terminals in it.
 
My system is very reliable now but I do have to recharge it every year or two and it is never as nice as my Grand Cherokee!
 
Clover said:
My system is very reliable now but I do have to recharge it every year or two and it is never as nice as my Grand Cherokee!
Click to expand...
I figured you could be of some help here.:thumbsup:
 
Check the Imperial club website, which I THINK has a page/section on it. Fortunately my otherwise LOADED '67 did not include the dreaded ATC 1, then known as "dial-a-prayer," which I think had it's own separate repair manual. Good luck with it!
 
What would cause the blower to stay in low speed all the time? (1972 New Yorker, auto temp II) Thanks
 
Probably the amplifier not sending the proper signals to the servo unit. All the fan speeds and vacuum controls are run thru the servo. You can get it to stop by pulling the 10 hose vacuum bundle off of the servo then plug the hose that's got vacuum on it.
But that's not a real fix. Just something to stop you from roasting alive.
Best to talk with the folks at performance analysis. The repair parts are around $700 for the servo and amplifier. But I would talk to them first! You can burn up an amplifier very easily as they are delicate.

LeBaron1973 said:
You could also message 73 T&C who has just fixed his 1978 unit.

Forum thread: what I learned about 74-78 ATC II

Good luck sorting yours out.
Click to expand...
Javier did a great job on that. Definitely worth the read, however, even though the theories are similar the mechanics of the systems are very different. On the formals all the action takes place under the dash and on the fusie's the action is under the hood so to speak, in the servo. Just hope that no one screwed with the "timing" of the servo. Or it could take a long time to sort it out.
The fsm has a lot of info but without the test equipment the dealers had, its a nightmare. Even with it it's mind numbing. Just check out the vacuum diagrams for the servo and what goes on in that thing!
Good luck, hope you have plenty of patience and beer!
 
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You can easily test the servo, by jumping +12v into the correct terminals at the amplifier. Performance Analysis has a one-page diagnostic sheet (very small writing, front and back) that walks you through the process.
 
7071 chally said:
Do you have a link to this procedure? Can't find it...Thanks
Click to expand...
Here’s the link:
865-482-9175
I said “Performance Analysis has...” I did not say “Performance Analysis has, available on their website...”
George Murphy is a friendly guy. Push the link and leave a message. He’ll call you back.
 
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Clover said:
The control system is actually pretty simple if you understand electronics somewhat. It’s all about maintaining equilibrium. The place to go for help and parts is Performance Analysis Co..
George Murphy can help you determine what you need, which is most likely a servo and/or amplifier. I needed both and also had corrosion at the amplifier connector and replaced all the terminals in it.
Click to expand...
Sorry, but I had to disagree... if it were as simple as you say it is, nobody would be bitching about it, and everyone would have a working system, and it wouldn't be an issue. Plain and simple, the system worked when they were new but VERY difficult to fix, diagnose, and repair in the later years. There is no guarantee, that after dumping $700 plus dollars, into two parts that it will work properly. It is well known that these are very problematic and intricate systems so please don't soft soap it and lead people to believe that it's an easy fix. It's just not so.
 
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