1987 Mercedes-Benz Mercedes Benz 190 Class "bull refrigerator compressor" Questions

Bull-CHIMG777-Conditioning-Manifold-Gauge/dp/B000VAQQ3Y/ref=sr_1_3?ie=UTF8&qid=1374522452&sr=8-3&keywords=r22+pressure+gauge Connect the red hose to the high pressure side located in front