I remember years ago there was a thread on wiring in a separate switch for manual control of the AC compressor. I dont really want to run wires to the engine compartment and rather handle it under the dash. I did a search but came up empty handed. Anybody remember?

TIA

Duncan

 

I am certainly no HVAC kind of guy, but having a manual switch that can be "forgotten" sounds risky to me. But I am an old guy with CRS.

 

No clue on the wiring for a switch. I just unplugged mine.

 

The Clutch is activated by System Voltage (12vdc). Only two poles (+) & (-). Any switch supplying 12vdc to the (+) side will activate the Clutch. Couple wires and a Switch with a Fuse will do the Trick.

Never used one to control the system except when I had a 85 Celebrity and a 76 LTD which had wiring issues. Did the same for an Electric Cooling Fan on a 88 Celebrity Wagon

 

The compressor clutch is powered in the max ac, ac, panel/floor, defrost floor, defrost positions.

To me its just a needless drag on the engine which in all reality is not a huge deal but I like flipping switches!

 

I also prefer a separate switch for the A/C but usually it's because some of the settings don't turn the A/C on and I want to dehumidify the vehicle while running the heat.

 

In the case described, I would pit an in-line switch in the current circuit. This way you can turn it off (open the circuit) or in the On (closed circuit) the pressure switch will control it as designed in the Summer months.

 

Agreed.
You need to find out what wire on the heater control feeds the compressor clutch and install you switch in that wire. That will keep the pressure switches functional. Those pressure switches keep the compressor from coming on when the outside temp is too cold or from over pressure, both of those conditions can destroy the system.

 

With the above in mind. Last year I replaced my compressor and dryer on my system. During the parts swap, my buddy cracked the low pressure switch housing so it started leaking. Ford upgraded or changed the part and changed the plug style so I needed a new pigtail. Ever since I put the new plug-in I noticed the compressor coming on even if the in dash controls were not an AC. Well, I thought the Low pressure switch was not working properly. It wasn't until Mark a.k.a. Walleye Hunter directed me to a thread that showed me what controls in the cab actually shut the compressor off or allowed to run as the Factory intended. I got ford to warrantee the low pressure switch, thinking it was bad, and instead of soldering the new pigtail in, I used butt connectors that could be unplugged, if I unplug the low pressure side the compressor will not turn on.

Here's why I gave you my life's story above. Keeping in mind what Pirschwagon stated and my experience with the low pressure switch, it may be easiest to just Tap in to that pigtail with a switch that will open or close that circuit and allow you to override the AC system altogether. Not sure if I'm in the right tracker on track just my two cents ...