I have an 01 Civic LX. I had the A/C compressor replaced last summer. Last month, I leant it to a friend for a road trip. He was driving it on the highway in just above freezing weather, and even though the heat was dialed all the way up, barely any warm air was coming out of the vents. So he pulled over and popped the hood, and found that the lines running to the A/C compressor were covered in ice.

When he took it to a shop, they said they'd seen this issue before, the compressor was probably wired wrong or else the relay was broken, and they pulled the compressor relay for the trip home.

Anyone seen this before and know what got done wrong?

 

When I've seen that happen it was a restriction in the line. Usually from not flushing or vacuuming all the debris from the system when the compressor takes a crap.