Ac blowing warm

High pressure switch possibly, and may still be low on refrigerant.

 

Only sure way to know if you have the proper amount of freon is to have it vacuumed and recharged.

 

Frozen expansion valve can cause it to not cool. Leave compressor off or leave truck off if you really want to troubleshoot. If it cools after that long waiting period I'd say expansion valve is freezing.

 

That's not the only way.

 

Do a Google search for resetting your ac.

Pretty common on the later FLs.
You didn't say what truck you have . I don't know if all manufactures provide a reset feature.

Clogged expansion valve.
Weak compressor.
Overcharged.

134 doesn't cycle the compressor like 12 did. Unless it's low on freon.

There's no coolant in the system.

Let your system sit overnight if you can. Check static pressure in morning. That'll tell you if it's low or not. Static pressure shouldn't be higher then 120 psi with outside temps at 110*.

 

In my opinion it is. Gages are not always accurate.

 

My old 379, after we installed a new evaporator. I blew so cold I had Crack the drivers windows even in 95 degree weather.

 

That's your opinion.
Experience says otherwise.
And gauges are accurate.
Even the machines us em.


And you need a new thermometer.

Max cold for 134 is 41*
Max cold for 12 is 35*

12 will frost. 134 only gets wet.
134 doesn't get as cold as 12.

 

When we charge my ac, we put the pounds in that my truck called for. I don’t remember exactly, but I think it to something like 5 or 5.5 pounds. And it was charged perfectly, whether the gage was accurate or not who knows, but is was super cold. I never even had to turn on the bunk ac. The machine has a guage, but we went by the pounds.