2012 6.2 XLT 50,000 miles with manual single zone controls.

I haven't had time to work on it yet, but it seems that my AC compressor is not engaging. The dash controls light up normal, fan comes on, etc.
I am just looking to see if there are any common failure points.
I know it COULD be low on charge, clutch could be bad, etc.
I am just checking if there is a common failure with these trucks AC system.
Thanks

 

Usually when low on refrigerant, the compressor won't engage so it does not do any damage. I would hook up gauges and see the amount of refrigerant currently in the system as a starting point.

 

low on refirigerant...cuased by a leak...cased by dormint AC.....basically to prevent seal leaks...turn it on regularly even in cold months to keep the seals conditioned.

 

thats why the compressor runs when the defrost/defog is on

 

I have read a few posts about evaporators leaking 2011-2012. I hope you don't get that diagnosis.

 

THIS! (what snowplowdriver said)

Just had my evap core replaced. It's pricey because the entire dash needs to come out to fix it. Google it and you'll see many mentions of this failure.

 

WRONG. Think about what A/C stands for. Air CONDITIONING, which doesn't necessarily mean cooling. When your mode selector is placed in the FLOOR/DEFROST position, it means the desired outcome is to defrost/defog the windshield (most noticeable during rainy weather). The purpose of the A/C compressor cycling in this setting is to remove moisture from the air, so as to achieve the desired purpose.

Which, as a Ford dealer licensed tech, I've seen my share coming through our shop. An easy way to confirm a failed evaporator would be to add A/C dye to the refrigerant, and watch for dye traces exiting the drain tube on the firewall while the A/C is operating.

 

well.................

 

Oh man, ouch. Going to pat mine on the dashboard on the way to work this morning...."good truck, good truck..."

Did you find it with the leak dye?

 

Good job. Are you doing the work yourself?

 

BB posted that the reason the AC (compressor) comes on in Defrost mode is to ensure that lubricant is circulated year round. That helps keep the seals fresh, keeps oil between the o-rings and the metal parts which reduces seepage, and minimizes corrosion of metal parts. He wasn't referring to a need for cooling in cold weather.
I understand that the AC system activates to reduce humidity to help keep the windows clear. Why would you tell him he's wrong? He isn't.