A/C compressor cycles when not selected

[Old_Sparky]

While changing the oil on my truck last night, I noticed that water was draining from the A/C hose from the firewall. I have not had the A/C on for the last month. I have the dash selector set to floor or floor/vent. With the engine running, I watched the A/C compressor cycle on and off. What would cause the A/C compressor to cycle on and off when the A/C is not selected?

[stodg73]

The A/C cycles when you have the defrost selected. This way the fluid inside gets circulated and the pump is lubricated. This is a normal operation for the A/C unit.

[Old_Sparky]

The problem is I do not have defrost selected. I am only using the floor selection or the floor/vent selection. In either of these, the A/C should not be running as far as I know. I am wrong on this?

[Wild and Free]

I think its normal in the dual position. Mine cycles the compressor when its in the dual floor / vent position also.Change it to floor or vent alone and it does not cycle. My 02 and 05 are both the same way.

[Old_Sparky]

Wild and Free, this makes more sense. Not sure why the factory decided to do it this way and not put the snow flake on the dash for us.

[Wild and Free]

I have always wondered why they did it that way also as its very odd. But it is what it is I guess.

[AH64ID]

My 98 ranger did the same thing when on face/floor..

I haven't noticed it on my 05, but also have listened/looked for it.

I wonder if the duty cycle is difference with the a/c switch on.

--- Update to the previous post...

Well I pulled this from my 05 Owners Manual.. It appears it only operates in the mix/defrost with the a/c off. My Ford manual specifially stated which levels it worked it.

NOTE:

The air conditioning compressor operates in

both Mix and Defrost or a blend of these modes, even if

the A/C button has not been pressed. This dehumidifies

the air to help dry the windshield.