How do I get a service manual for a refrigerator?

Actually the least hassle is to write down the model and serial and contact the manufacturer, you can dig through the internet but it can be a long drawn out frustrating challenge, many are posted as pdf files either view on screen or print, but if there is a printed manual for the device calling customer service should get you one, with possibly a small charge for shipping, many devices now have no printed manuals and you are directed to a website to download, that might work, and may be the only way to get a printed manual it depends on model and make, but if you have the model and serial in hand calling customer service should get you what you need,