a/c clutch engaged when defroster button pressed?

[bobfist]

a/c clutch engaged when defroster button pressed?
Is this normal in a charger rt se 1969?
Everything original

[histoy]

I believe that it engages briefly to dehumidify the air going to the defroster.   On my '68 there was a vacuum sensor/switch on the AC unit under the dash that would disengage the clutch after a brief time.

[Mopar4me]

Yes it is normal. It's the controlled by the Time Delay Relay which will run the A/C for a period of 1 to 10 minutes when the ambient temp is above 25 Deg F and the defrost or heat buttons are pushed.

[bobfist]

yes the time delay shuts it off in heat mode but engage it again if i press defrost

[bobfist]

can it be the new vacuum switch block that is wrong inside?

[bobfist]

seems that the blue wire got 12 v back on the vacuum switch when i press def, i guess the repro is wrong inside

[bobfist]

Can it be soo that in def mode it runs the ac the wwhole time to lubricant the system. Bec it turns off the ac in heat mode after a while

[bobfist]

Here is the time delay when its above 25 deg
notice the orange rubber stop are stopping the vacuum to escape


Here is its after a while in the freezer, now the rubber on the tempsensing metal moved away from the port and the vacuum cant turn the ac off


is it so that the vacuum restrictors on the hoses are the "time delay"

[john108]

How easy is it to open the time delay?? To look inside.

[bobfist]

No just bend the Metal lid Open.
But cant someone answer what it is here inside that makes it 1-10minutes

[Mopar4me]

Information was take from the factory service manual. There is no info on testing it though.

[bobfist]

No, noone knows how it works i think