A/C: Anti freeze Switch?

[tk826]

Air conditioning went out.
Having it repaired.

As explained to me, the trouble is a bad "Anti Freeze Switch" (separate words), which is located around the heater box area.
Apparently it is an AC cut off Switch tied to the drier, to keep the system from icing over.
The solution I'm told, is to find a new one, or bypass it, as there is another, more important cut off switch, tied to the compressor.

I can find no mention of a "Anti Freeze Switch" in the "Mopar 1974' Parts catalog" , nor the "Body and Chassis Manuals".
Is anyone familiar with this part... perhaps by another name? Is it possible to find another?

Thanks.

[AZBlues]

He probably means the binary or low pressure switch, located on the drier.



Howevers, the drier is on that bracket mounted to the right of the radiator, far away from the HVAC box. The device mounted inline at the firewall is the TXV, or thermal expansion valve. That's what regulates the flow of refrigerant going into the evaporator, based on the heat of the gas coming out of it.

The binary switch detects if the operating pressure is too high or too low and cuts power to the compressor to prevent damage. Both can cause the same symptoms if they are malfunctioning. You are supposed to replace the TXV whenever the system is opened, and at $15-$20, there is no reason not to. Replace the binary switch as well, they are cheap and pretty standard across a lot of different makes.

[tk826]

The first diagram, is from the 1973 chassis manual (listed under DART) , showing the Freeze Switch.

The second is from the 1974 Chassis Manual, (Listed under DART and Valiant).
Only thing missing is the "Freeze Switch".
Couldn't find a diagram, in either years, specific to the Monaco.
Although, I'm guessing, according to the info I have. it must follow the 1973 diagram.

[flcl64]

The A/C in my truck had a valve in the compressor to keep it from freezing, when I converted it to 134a the valve had to come out and a thermostatic switch had to be put in it's place.



I mounted it under the dashboard on top of the heater box, the probe just pokes into the front of the evaporator and it splices into the signal wire going to the low pressure switch as they both just cut power to the clutch. I recommend putting a relay to the clutch since in my experience, there tends to be a lot of resistance in all the extra wiring and switches, if the clutch doesn't get full power it will slip and blow itself apart in no time.

[AZBlues]

I can safely say that my '75 does not have one. Is it needed? IMO, no - especially with R134.