Sorry to be reverse of everyone else but my A/C gets too cold and maybe some of you guys are having the same difficulty but just haven't realized it because it starts blowing warmer air after awhile.

So heres the problem, A/C runs real cool then after 20 min's or so its no longer real cool and only keeps the truck barely comforable if that. What seems to be happening is the core under the dash is freezing off with frost to the point that it wont allow air flow through the core, turn off the A/C for 10 - 15 minutes and all is good again, you can notice that the blower isn't blowing as hard too cause it won't pass much air through the frost. How can i stop this core from freezing off. Is it as simple as turning up the temp dial a little instead of having it all the way over to cold?

That happens when your are low on R-134. Causes it to freeze up

I had the same problem on my 94. I can't remember for sure but I think it did help to turn the temp up a hair. I know what the final solution was though.....I sold it!:lol: But seriously, mine was fine and then had a new compressor etc installed and then forever after I had the freeze up issue.

Ditto to Bowtie's response. Had the same thing happen last summer. Filled it with freon, and it was fine.

Now I have a leak somewhere, and she won't hold freon past two days. But we'll get it figured out, about the time summer's over.

I have a jumper where the low pressure cycling switch should be and I have to turn it off for a second ever now and then or it will freeze up as well.

Mine will do that if I run the AC on low, but if I keep on high it don't do it WHY????

Carey

the air coming in the duct is warmer than the evap core temp. Slow the air down and the core get's colder, speed the air up and the clutch will stay engaged longer to keep the evap core colder. Put on the reciculator and the air re-entering the core gets dryer and colder and increases the chances the core will freeze.

PS and if it's humid enough the core can freeze solid on the outside with ice.

Pressure is going too low while cooling. Possibly could happen with low on refrigerant situation, but more likely, your low pressure switch is goofed up. Monintor with gagues and see where is switches at. If the compressor constantly stays engaged, it will freeze the coil when properly charged. There is a chance it can happen with low on charge, but the possiblity is a whole lot less, only because it is a pressure switch controled system. When the pressure drops, the compressor cuts out. In a low charge situation, it drops quickly, and so quickly, that it doesn't remove heat well and freeze up the coil. If you are low on charge and the compressor stays engaged, it will freeze up, but then again, it's back to the pressure switch.

Check the cut-in and cut-out of low pressure switch. THEN adjust the refrigerant charge if need be.

Pressure switch is an easy change, threaded with shreader, so you don't have to pull the charge from what I hear.