Automotive Air Conditioning Information Forum

Well, you have changed the pressure switch at least once. What is the low side pressure when you believe you are seeing ice buildup on the evaporator?

You could simply adjust the cut out pressure up a little on the cycling switch - IF it is in fact building ice.

The evap freezing up is a symptom of the clutch not cycling. I'm not 100% sure it is freezing up, just a guess. Fix the clutch cycling issue and don't have to be concerned about evap freezing, if in fact that is what is happening.

Very nice looking, clean Suburban by the way. I used to live in your area, so I know a little something about the Texas weather.

Here's another thing you could try, although a bit of a nuisance: When you think it might be icing up, pull over and look at the drain tube underneath. If little to no condensate is coming out, watch it for another five minutes or so. If suddenly you see a lot of condensate draining, then the evaporator is probably freezing.

As I have stated earlier, not so much concerned about the freezing up issue as I am about the clutch not cycling. I only mentioned the freezing up part because after an hour drive the interior a/c case starts to sweat. Clutch cycling properly don't have be concerned about possible freezing up, condensate dripping from the interior case, etc. This system is designed to cycle, and it doesn't. Ever!

I would take the advice of bohica2xo, then, and adjust the low-pressure switch upwards in small steps until you see the compressor begin to cycle. Other than that, the system seems to be performing pretty well.