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Air conditioning help (Cold when cool out, hot when warm outside)

Hello, perhaps someone can help. I have a 1999 Honda Accord that will blow cold air when it’s cool outside (the commute to work in the morning or a rainy day) but if it’s sunny outside or warm the a/c blows hot air. The compressor never seems to shut off, sometimes on trips longer than an hour the entire condenser freezes solid. Any suggestions as to what can be causing this or how to fix it?

Condenser freezing solid? Never seen that. Do you mean the evaporator freezing solid? If so, the problem might be with the expansion valve. This is what converts the high pressure liquid back to a low pressure gas at the evaporator. It’s not uncommon for these expansion valves to fail to where they no longer control the conversion of the liquid refrigerant back to a gas which causes the evaporator to freeze over.

Tester

Yep, you’re correct, evaporator freezing solid. The expansion valve was replaced in an effort to fix the issue.

OK. Was the condensate drain tube checked to make sure it wasn’t plugged?

Tester

It was checked, no blockage.

Then the problem could be with an overcharged system. I’d go back and check the line pressures, with the engine idling at 2,000 RPM’s, a large fan blowing at the condenser, and making pressure corrections for the ambient temperature.

Tester

Great, I’ll check it out, thanks for your help!

Some cars have a evaporator temperature sensor that cycles the compressor off when the evaporator gets to cold to prevent the the coil from freezing up. Perhaps its a defective Evaporator temperature sensor, or Low pressure sensor/switch depending on what device the car uses.