A/C questions, AutoTemp II, part two

["Robert Weldon" <rweldon@xxxxxxxxx>]

I finally had some time to apply some of the suggestions from my previous post on this subject, my thanks Dave Duricy for his response to my previous post, and I pulled apart my Autotemp II servo unit, mostly to see if I could figure out how it is supposed to work, and now I have some further questions.

 

First off, I checked the master and fan switches on the heater box on the car.  I found that the fan switch was bad and wouldn't hold vacuum, so it wouldn't turn on.  The master switch seemed to be ok.  Anyways, I jumpered both switches with short pieces of wire, so now they are permanently "on" and I have a functional fan.

 

Just today I took apart the servo unit, and found that there was signs of fluid in the part of the casing where the big motor thing is, the other three quarters of the casing were clean.  After starting the car, I watched the servo as the car warmed up, to see if I could see any signs of it functioning.  I didn't hear any noises, and when I pulled the case apart again, with the engine still running and at operating temperature, I noticed that the motor on the bottom of the unit would turn very slowly, and only if I helped it.  The system appeared to be stuck on high heat, no amount of changing the temperature knob would change the temp, nor would changing from low to high a/c or how or high defrost, and there was no sign of the A/C compressor clutch working.  I also noticed a slight amount of coolant inside the casing, again in the part where the motor goes, although I could not see where it was coming in, and it remained only a small amount on the bottom of the housing.

 

My questions are, how do I test this motor in the servo to see if is in fact, actually working, and are replacement motors available and at a reasonable cost.  Also I couldn't figure out the purpose of the smaller motor mounted in the top part of the server, it never seemed to do anything while I played with the system, and I couldn't determine it's purpose.  And finally, how do I know if the a/c compressor clutch is engaged, I am assuming the outer part of the pulley should be spinning with the pulley?  This was not turning when I checked it, no matter what setting I put the a/c controls at, including off. I am assuming this means the clutch has failed, or the compressor is not getting a signal to engage the clutch?  Strangely, I seem to remember the last time I played with the system, the outer part of the clutch was spinning.

 

Anyway, I am hoping I can get some answers or suggestions from the gurus here, otherwise I will have to spend actual money at an a/c specialist in town, although I don't want to spend money getting the refrigerant flushed and changed over until I know the system is functional.  And I am not to keen on paying their hourly charge for them to troubleshoot things, although I am beginning to suspect that this system is beyond my ability to troubleshoot.   I may be able to swap on a borrowed unit from another car, known to be functional, so I can at least determine, hopefully, if the a/c compressor is funtional.  

 

Robert Weldon

 

72 Imperial 2 dr (for sale)

68 Newport conv.

75 Dodge Dart Sport (factory air, presently missing a/c compressor)

97 Plymouth Voyager Minivan