'06 Mitsubishi A/C stops working

My 06 Mitsubishi Galant’s A/C quits blowing air after approximately 50 miles of driving. The fan is running normally but the ducts don’t have much air coming from them. I let the car set for a period of time and it starts working again. It acts like the coils are freezing up. I had a mechanic check it, the freon is ok, there is no cabin filter and they replaced a relay hoping to fix it. So far, no luck.

Thanks,

The fan is running normally but the ducts don’t have much air coming from them

Its pretty hard for both of these things to be true at the same time - unless you mean that the air is blowing out just fine, but that its not very cold. If your fan is blowing away but little to no air is coming out then the problem has to be inside of the ductwork with the directional doors. I’m assuming you mean it stops blowing cold after a while?

I take this to mean the blower motor sounds normal but little air is coming out of the dashboard vents? If so, it could well be that the evaporator coil is freezing up.
This can be due to the refrigerant being a little low, a problem with an expansion valve, or a problem with the compressor controls, etc. I think this model of car uses a compressor control module which is mounted in the center console.

Before getting too deep into the low refrigerant thing I’d have to know what the pressure readings were, how they were taken, etc. If your mechanic slapped gauges on and checked the pressures while the engine was idling in a shop that may not reveal a whole lot about what’s going on.

Next time it acts up, stop the car and look underneath the passenger front floorboard to see if there is a condensation drip. If not, the unit could be frozen.
Turn the A/C off and check underneath again in about 5 to 10 minutes. If a drip has now appeared then the unit is freezing up and you’re seeing it thaw out.

Thanks for trying to help!
Actually, the fan IS blowing away but little air is coming out. I thought about the directional doors but this happens even though the direction knob hasn’t been moved.

As for the method of checking the pressures, I don’t know the exact steps they took. It does, however, act JUST like the A/C in your home when it freezes up. The blower works great but it cannot move any air due to the ice. I’ll try and look under it hopefully this weekend.

Thanks again.