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Discussion Starter #1
Selectaire (York) keeps running. Even on "Heat," compressor is still cycling. Cold air out the top vents, hot out the bottom! What needs fixin? Thanks
 

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I don't know for sure on your 65 but most cars turn the a/c compresser on when in deforst mode [ air coming out of top vents] It should not do it in heat mode, but then air would not be coming out of top vents. Check control position and adjustment ??
 

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Only things I can think of would be to chech the connections that you can get to (electrical) for corrosion, then look for a vaccuum line that is off or leaking. Seems odd that a vaccuum leak would stick the compressor 'on', but vaccuum controls are mostly voodoo and witchcraft anyway. There is also a vaccuum manifold in the heat/air control on the dash (guessing on '65) that controls the doors and blender, those are bad about leaking and just falling apart. As a temp fix, you could remove the belt for winter.
 

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Discussion Starter #4
It doesn't run when the fan is off. But then neither does the heater!

Actually I am hearing a noise, a kind of graveley sound intermittently from the compressor. I wonder if it is on its last legs?
 

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Pull the clutch wire from the compressor, while its running to see if it stops. If not it prolly just needs a whack with a hammer (not really but would tell you your issue)

1 stays on, clutch is stuck
2 turns off, check your switch connections in the dash.
 

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If the compresser shuts off when you turn off the blower motor, Then your compresser and clutch are working normal. I would look at the switch on the defroster that would normally turn on the a/c when you use your defroster. I am not sure where that is on your car. Your shop manual should show it.
 

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Discussion Starter #7
I believe when I move the lower lever to defrost all that happens is the vacuum motor moves and the air in the plenum is redirected. Nothing more sophisticated than that in 1965!

When the heater is on I can look at the engine and see the A/C clutch cycling on and off like I have the A/C on.
 

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OK wild guess is there a switch on the control panel that would be tripped when you go to defrost ? If so it could be stuck in the on position. ??
 

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Discussion Starter #9
I'll get under there and have a look.

What is it anyway that makes the A/C decide to turn on? Well the fan switch is one thing. But what is the other?
 

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Discussion Starter #11
AC operation is Fan switch combined with the heater control lever being in the AC position.
yes yes yes, I've got the owner's manual. I want to know what does that position actually do to make the AC come on. Then I can track down the problem.
 

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It supplies 12Volts to the low/high pressure cut off switch then through that to the compressor clutch.

If the pressure in the system is ABOVE specs the voltage passes the switch and engages the electric clutch on the compressor.

If the Pressure in the system MAXES out the High pressure switch (Some rig's don't have one or they're the same switch) then it Cut's power to the compressor's electric clutch.


That good nuff fer ya?
 

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Discussion Starter #13
gettin there, you are pulling me through the keyhole. To paraphrase, when the lever at the dash on moved to AC it closes a switch sending 12V to the compressor. But those volts stop along the way to get a final go-no go signal, from the pressure cut off switch.

So if my compressor keeps running the problem will not be in the pressure switch, because I can see the compressor coming on and off. It will be in the dash, where the circuit is staying closed even when I move the lever?

Just to be sure on the lever, do you mean the top lever which is the cable, or the bottom lever, which is the vacuum hoses?
 

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Discussion Starter #15
It would appear the thermoststic switch combines the activation from the cable and the sensor into one unit.

I pull the lever over to HEAT and the clutch continues to engage/disengage as it nothing happened. When I pull off one ot the switches wires, the clutch stops. So I think I have found the culprit, don't know where to get a replacement though.
 

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