AC seems to be running all the time - ????

[98v70dad]

I've been watching a little coolant leak (more like a seep) on my 96 Ranger so I've been paying attention to puddles under it after going for a drive. Today, I was running a bottle of Prestone coolant clean through the system so I can do a good flush and fill. To do a good job I had the heat and fan on high to insure I had thorough coolant circulation. So my air conditioning was OFF. Yet, each time I stopped for a few minutes (home depot, bank, grocery store) there was a puddle of crystal clear condensate from the AC on the ground in the usual place. I got down close and put my hand in it to be sure - clear water, no smell. So, why would my AC be running when I had both the heater and the fan on maximum? I'm in Atlanta so the heat in the cab was almost unbearable. Something may be wrong with the AC but generally I wouldn't notice it because I run it almost all year long. It is usually on or the AC/heat dial is selected as off.

 

[sgtsandman]

Open the hood with the A/C turned off. Look at the A/C compressor. Is the center part of the A/C pulley turning? If so, It’s running uncommanded. If not, it’s fine.

With a ‘96, the A/C should only be running in three settings. A/C, MAX A/C, and defrost. The A/C helps clear the windshield faster, this why it runs in the defrost setting. When the settings are on dash only, dash and floor, or floor only, the A/C should not be engaged.

 

[rubydist]

I believe that dash/floor also commands the a/c to run.

When its hot out and the a/c is properly charged, the a/c will run continuously as there is enough pressure to never trip the low pressure cycling switch. So most likely it was doing what it is supposed to do.

 

[RonD]

If a vehicle made after 1994 has AC then it will be on in all positions except OFF and VENT
If the control doesn't have VENT then AC is only off when OFF is selected

The reason its that way is to DRY the air coming into the cab to prevent musty smells or mould
And in OPs post it is obvious there WAS moisture in the air to DRY out as there was water dripping out of Evaporator tray

In 1994 and older AC was activated with AC on but also when DEFROST was selected, for the obvious reason, to DRY the air blowing across the windshield so it could absorb more moisture and clear the windshield faster


AC can only cool the air down to 38-40deg or so, but not really since incoming air is usually 80-100deg
The Heater core runs at 180+ deg
So there is no battle between heating and cooling, heater ALWAYS wins, lol

TEMP Control has no connection to AC or heater core
It just routes the air from blower/evaporator either thru the heater core or around it, or anywhere in between
Called the Blend Door, cable operated 1994 and earlier, electric motor 1995 and up

 

[sgtsandman]

I believe that dash/floor also commands the a/c to run.

When its hot out and the a/c is properly charged, the a/c will run continuously as there is enough pressure to never trip the low pressure cycling switch. So most likely it was doing what it is supposed to do.

This is true, starting at a certain year. RonD seems to have answered that. My 1998 didn’t have A/C, so I have no basis for comparison.

 

[sgtsandman]

If a vehicle made after 1994 has AC then it will be on in all positions except OFF and VENT
If the control doesn't have VENT then AC is only off when OFF is selected

The reason its that way is to DRY the air coming into the cab to prevent musty smells or mould
And in OPs post it is obvious there WAS moisture in the air to DRY out as there was water dripping out of Evaporator tray

In 1994 and older AC was activated with AC on but also when DEFROST was selected, for the obvious reason, to DRY the air blowing across the windshield so it could absorb more moisture and clear the windshield faster


AC can only cool the air down to 38-40deg or so, but not really since incoming air is usually 80-100deg
The Heater core runs at 180+ deg
So there is no battle between heating and cooling, heater ALWAYS wins, lol

TEMP Control has no connection to AC or heater core
It just routes the air from blower/evaporator either thru the heater core or around it, or anywhere in between
Called the Blend Door, cable operated 1994 and earlier, electric motor 1995 and up

Floor only shouldn’t have the A/C running either. That or my 2011 has been broke from day one.

 

[RonD]

Yes, in 2010 I do see that PANEL and FLOOR do not turn on the AC, so most likely the same for 2011

In 2008 all vent selections turn AC on except OFF

In 2006 just VENT has no AC on
Wasn't going to go thru all the years, lol

But suffice it to say that AC is ON more than OFF in vent selection

 

[gw33gp]

My 2002 has no A/C on panel or floor positions. A/C is on with all the other positions.