Can't remember exact locations. But here is how to find it. From the compressor, follow the hose/tubing to the dryer(Big aluminium container). In the tubing you see it go from one size to a smaller size. This is where the orifice/expansion valve is. There will be a coupling to take apart. It can be two nuts to unscrew or a quick disconnect coupling. There are tools to pull it out. I just ground down a pair of needle nose pliers to pull them out. Twist it as you pull it out.