This is for my 00 b5 1.8t qa had the motor installed awhile ago last year guy charged the system but said the compresser wouldn't engage but if he manually jumped the compresser it would work. What is wrong there was only one hvac code for high pressure valve but has since been replaced any ideas

 

There are many things that could keep the compressor clutch from running. For starters, check the low-pressure switch. If that is an open (not completing the circuit) for any reason, due to a defect or actual low pressure, the clutch won't engage.