RV2 compressor will not disengage

[Straight eight]

Hi to all,
two weeks ago i converted my a AC to R134a. I bought the car 3 years ago (a 1973 Chrysler New Yorker) with a non functional AC. I thought i give it a try to convert it to R134a. Took the system apart...flushed the hoses...installed all new o-rings, new dryer, Ester oil. Vacuumed the system and put 85% of R134a in it for what it called for R12...and big success!! And believe it or not....it blows really, really cold now... so far so good. The problem: The compressor will not disengage when i turn the AC off. It will only disengage when i turn the heater lever in the hot position and turn on the def or heat button. What could be the issue?

Thanks for your help, Marco

 

[CBODY67]

Starting in 1972, the a/c compressor runs all of the time, even in the "OFF" position . . . with the normal manual a/c system. I discovered that on our '72 Newport Royal 400 2bbl, when it was new. The alleged reason is that the fan ALSO runs at a very slow speed, such that it keeps fresher air in the hvac box, such that when you turn on the defroster in a cold and humid atmosphere, the windshield does not fog up as much.

How to get the compressor to turn off? IF you move the heat lever toward "HOT", about half way there (from "COLD") you can feel and hear a faint click from under the dash, which is repeatable going either direction with the heat lever. When the lever is to the hot side of that click, the compressor is off even in "OFF". To the cold side of the click, the compressor is on, even in "OFF".

The heater cable has a junction in it that runs an item which depresses a switch in the compressor power circuit. Might just jumper the connections and see what happens? Or unpliug one of them, taping it if needed? Either way, you want the compressor running when the a/c switch is on.

Another thing which can be easily done is to move the heat lever just past the click and then reposition the heater water valve position to be closed with the heat lever in that new position. There should still be plenty of hot water on cold days for sufficient interior heat, as I recall. Just that it looks kind of different to see the heat lever at mid-travel.

There might be a Chryselr MasterTech video on how the '72-'73 hvac system operates at www.mymopar.com.

Enjoy!
CBODY67

 

[413]

Just find the wire heading out to the compressor clutch and install a manual switch.

 

[CBODY67]

Just find the wire heading out to the compressor clutch and install a manual switch.

Which is what some law enforcement people did.

 

[Slap Stick]

LEO cars usually had a factory switch installed.

 

[rv2]

Hi to all,
two weeks ago i converted my a AC to R134a. I bought the car 3 years ago (a 1973 Chrysler New Yorker) with a non functional AC. I thought i give it a try to convert it to R134a. Took the system apart...flushed the hoses...installed all new o-rings, new dryer, Ester oil. Vacuumed the system and put 85% of R134a in it for what it called for R12...and big success!! And believe it or not....it blows really, really cold now... so far so good. The problem: The compressor will not disengage when i turn the AC off. It will only disengage when i turn the heater lever in the hot position and turn on the def or heat button. What could be the issue?

Thanks for your help, Marco

I discovered the same thing on the 73 Polara I just purchased.

 

[Ripinator]

Hi to all,
two weeks ago i converted my a AC to R134a. I bought the car 3 years ago (a 1973 Chrysler New Yorker) with a non functional AC. I thought i give it a try to convert it to R134a. Took the system apart...flushed the hoses...installed all new o-rings, new dryer, Ester oil. Vacuumed the system and put 85% of R134a in it for what it called for R12...and big success!! And believe it or not....it blows really, really cold now... so far so good. The problem: The compressor will not disengage when i turn the AC off. It will only disengage when i turn the heater lever in the hot position and turn on the def or heat button. What could be the issue?

Thanks for your help, Marco

Add my '73 Newport Navajo to the list.

 

[Ripinator]

Starting in 1972, the a/c compressor runs all of the time, even in the "OFF" position . . . with the normal manual a/c system. I discovered that on our '72 Newport Royal 400 2bbl, when it was new. The alleged reason is that the fan ALSO runs at a very slow speed, such that it keeps fresher air in the hvac box, such that when you turn on the defroster in a cold and humid atmosphere, the windshield does not fog up as much.

How to get the compressor to turn off? IF you move the heat lever toward "HOT", about half way there (from "COLD") you can feel and hear a faint click from under the dash, which is repeatable going either direction with the heat lever. When the lever is to the hot side of that click, the compressor is off even in "OFF". To the cold side of the click, the compressor is on, even in "OFF".

The heater cable has a junction in it that runs an item which depresses a switch in the compressor power circuit. Might just jumper the connections and see what happens? Or unpliug one of them, taping it if needed? Either way, you want the compressor running when the a/c switch is on.

Another thing which can be easily done is to move the heat lever just past the click and then reposition the heater water valve position to be closed with the heat lever in that new position. There should still be plenty of hot water on cold days for sufficient interior heat, as I recall. Just that it looks kind of different to see the heat lever at mid-travel.

There might be a Chryselr MasterTech video on how the '72-'73 hvac system operates at www.mymopar.com.

Enjoy!
CBODY67

Hey! Thanks for this handy tip. I'll give it a go in my Navajo. Hey! I'm a poet!

 

[Straight eight]

Starting in 1972, the a/c compressor runs all of the time, even in the "OFF" position . . . with the normal manual a/c system. I discovered that on our '72 Newport Royal 400 2bbl, when it was new. The alleged reason is that the fan ALSO runs at a very slow speed, such that it keeps fresher air in the hvac box, such that when you turn on the defroster in a cold and humid atmosphere, the windshield does not fog up as much.

How to get the compressor to turn off? IF you move the heat lever toward "HOT", about half way there (from "COLD") you can feel and hear a faint click from under the dash, which is repeatable going either direction with the heat lever. When the lever is to the hot side of that click, the compressor is off even in "OFF". To the cold side of the click, the compressor is on, even in "OFF".

The heater cable has a junction in it that runs an item which depresses a switch in the compressor power circuit. Might just jumper the connections and see what happens? Or unpliug one of them, taping it if needed? Either way, you want the compressor running when the a/c switch is on.

Another thing which can be easily done is to move the heat lever just past the click and then reposition the heater water valve position to be closed with the heat lever in that new position. There should still be plenty of hot water on cold days for sufficient interior heat, as I recall. Just that it looks kind of different to see the heat lever at mid-travel.

There might be a Chryselr MasterTech video on how the '72-'73 hvac system operates at www.mymopar.com.

Enjoy!
CBODY67

Thank you so much for the info!!! So i assume everything works correctly on my cars a/c system...Yes and you´re right: when i move the lever about half way i can hear and feel a faint click....nevertheless i´m still a little insecured: you wrote that when the lever is on the hot side of the click, the compressor is off, even in the "OFF" position...to the cold side it is on, even in "OFF". Thereafter you could turn off the compressor by moving the lever toward "HOT". But in my case you have to press also "HEAT" or "DEF"....otherwise the compressor is still on. Can someone confirm this?
Thanks, Marco

 

[CBODY67]

I asked the local Chry dealership service manager about it running in "OFF", which is what it's supposed to do, later confirmed. But I still want it to be off, as it was on our '66 Chrysler, so that's when I found the "click", then repositioned the lever's cable on the water valve so the water valve was off when the lever was on the hot side of the click, but no water was flowing into the heater core at that position.

Now, if the outside ambient temp is below about 32 degrees F, the compressor circuit has a temp switch that cuts power to the compressor at that lower outside temp, too.

Enjoy!
CBODY67

 

[Ripinator]

Thank you so much for the info!!! So i assume everything works correctly on my cars a/c system...Yes and you´re right: when i move the lever about half way i can hear and feel a faint click....nevertheless i´m still a little insecured: you wrote that when the lever is on the hot side of the click, the compressor is off, even in the "OFF" position...to the cold side it is on, even in "OFF". Thereafter you could turn off the compressor by moving the lever toward "HOT". But in my case you have to press also "HEAT" or "DEF"....otherwise the compressor is still on. Can someone confirm this?
Thanks, Marco

I can confirm that the compressor on my '73 Newport Navajo turns off when I move the Temp lever to the right, until I hear the 'Click', with Off button depressed. I am very glad to have learned of this quirky workaround.