I took my car to the local garage to charge the AC is it does not get cold but i was told it was full. They the plugged it into the computer and it came up with the error below and could not fix it:

B393B-04 air conditioning compressor valve control circuit - open


A quick google says its a possible short, can anyone give me an idea as to what to look at, i have a meter to check shorts but not sure what loom or where to look.

Thanks