AC line freezing on truck

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So I asked a question about the ac blowing hot and cold randomly on my truck and I looked at it today and put my hand on the accumulator/drier and it was about as cold as a can of coke, maybe a little warmer. the two lines coming out of it were even colder like 40 degrees. Now their was another long line that went from the firewall over to the fender well and it looked like it was painted white, but it turned out it was actually ice!

Any ideas on what's going on? Is it low on Freon? I did have them replace everything but the condenser and the evaporator core.
 
I'm assuming this is like most American trucks and a CCOT system. The accumulator and large line leaving the evaporator should be slightly colder than the small line going in after the orifice tube. If you look closely, that line on the fender should come from the condenser. Somewhere between there and the cabin there will be a connection and at that point it changes from warm to cold. Inside that connection is the orifice tube.

What you have (plenty cold after the OT, but only moderate at the evaporator outlet) is a sign of undercharging. Put an accurate thermometer (not an IR gun) in one of the vents and observe the air temperature inside. It should be close to 40 F.

A tendency for the whole system to ice up means that the pressure switch is not working, or the refrigerant is contaminated with air (from improper servicing.)
 
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