Volvo 2013 VNL ac problems, evaporator freezing.

My Volvo also freezes and I can't figure out the problem for years. Changing expansion valve did not help. Maybe will try another expansion valve and blow air thru AC lines, to see if there is any debris in there

 

Is there any cold air coming from the system going down the road?
There is a pressure switch that should turn the engine fan on at 250 PSI.
The fan kicks in and the pressure should start to drop. There is another
pressure switch that will shut the system down at around 300 PSI so the
belt or a line doesn't fail. If the A/C fan switch is'nt turning the fan on then
the pressure will keep climbing until 300 PSI and the high pressure switch
shuts the pump off.
Ice building up on the lines is not unusual and not a sign of a problem.
When you say the evaporator freezes is it getting a bit of frost build up
or is it freezing solid?

 

@Rideandrepair

 

I have not had a lot to do with Volvo A/C units mostly pumps and lines fail.
There is probably a thermister in the heater A/C unit. The evaporator core
should run at 34 degrees so ice does not block it. Condensation forms on
the cold evaporator and drains through a drain in the bottom of the heater
A/C unit. The thermister maintains the minimum temp in the unit.

 

If it’s the expansion valve sticking, it will usually cause it to blow warm inside. Turning off the a/c letting it defrost for a minute, then turning it on again restores proper cooling. Usually a sign of moisture in the system, as a tiny piece of ice, gets stuck in the valve blocking it. The valve could just be sticking. Sometimes you can get lucky, turning it on and off and tapping on the expansion valve. Sometimes a small overcharge can cause icing. If you have a bunk system, hows it working? Are the lines icing up? Occasional icing of the lines isn’t always a problem. Mine does it sometimes. I think it may be when humidity is low, and outside temps are below 80. I don’t really know. New expansion valve, dryer, vacuuming the system and an exact amount recharge by weight amount, should fix the problem. I’m not familiar with Volvo. Seems a lot of things are unique to them. I don’t know why the blower would stop working.

 

Good point, is the thermistor the temp probe? Mine controls the compressor, on and off. Maybe Volvo also controls the vent door?

 

Before jumping to conclusions. Was the A/C working good until just recently? Have you looked for small leaks? It may just be a bit low on Freon. A very slow leaking seal behind the clutch is a common problem. Low Freon will cause icing too.