then fix it

Yes ice forming on the line usally indicates the freon level is low. You possibly have a leak in the system. First check your furnace filter to make sure that isn’t caked with dust. Improper air flow around the cooling coil can cause the system to freeze up also.

It sounds to me like the coils need to be cleaned out because the evaporator can not do its job properly.

1.) shut the unit off and let all of the ice melt.

2.) take an air hose or a vacuum, or a garden hose and clean the coils out (the part with all of the little fins)

3.) turn it on again

if this doesn’t fix the problem, then you might have a refrigerant leak somewhere in the system.

LJC is right. It more than likely is an air problem. If everything is clean and the blower is running at high speed, then the only other problem would be the refrigerant levels.

How cold is it outside? A/C units tend to freeze up when the ambient temperature is below 65 degrees.

Check to be sure your evaporator coil is clean and your filter is clean. If you recently switched to a high efficiency filter try changing back to a fiberglas filter. Some high efficiency filters restrict the air flow too much.

If none of these things help you will need to have a tech take a look at it. Something is probably starving the evaporator which causes it to ice up. It could be the system is low on refrigerant or the metering device is bad or obstructed.