2004 Ford Taurus Emissions Light on

I just recently had a new compressor and clutch belt put on. After driving it home, i noticed the emissions light had come on. Should I take it back to the shop where they fix the air conditioner(thinking he may or may not have done something or should i take it to another shop so they can check out the diagnostic.
Please advise just paid out $1000.00. for air conditoner.