Ac blowing at 55 degrees....

Which problem? We have two threads in one here.

 

Also, a note... if the blend door is working properly there is no need to shut the hot water off. If shutting the hot water off makes the AC colder, then the blend door is partially stuck open and you will get poor performance even if you shut the water off. It will be mixing your cold air with warm air from outside.

 

When I was home in Omaha last week it was 100 degrees and mine was blowing 58 degrees .
So shoved a wire up the drain tube and about a half a gallon of water come shooting out .
Next checked the intake on the floor on pass side ( 2000 fld classic) and yanked a shop vac full of dust bunnies out .
In Laredo now and gotta run fans on low to keep from freezin to death .

 

No it won't cause the evaporator to freeze up. A modern TEV system with a block style expansion valve, senses the temperature of the refrigerant coming out of the evaporator and regulates the flow of refrigerant to prevent freezing.

Some will also have a thermostatic switch to sense the temperature of the evaporator and shut the compressor off if it gets too cold.

That being said, some systems are set right on the edge of 32 degrees to give good performance. A plugged up filter will cause low air flow and can ice up the evaporator. And because ice is 32 degrees it may not be enough to trigger the thermostatic switch.

 

And like @NorthernMechanic and @bzinger said, if the drain is plugged, you'll get poor performance as well.

 

Might be partially plugged ...mine was draining too , just not all of it and was extremely humid .

 

Should have an expansion valve on that. Pull the cover off on the firewall side, you might be surprised at how much crap has collected in there.