testing air pressure sensors

I purchased Y2k's a few years ago for my camaro and they had the air pressure sensors still on them. I seen on Ebay that they are worth some $$$. I want to list them but don't know how to check if they are in good working order. I need Christmas $$$ so if anyone can help I sure would appreciate it .:confused:

take them to a chevy dealership. they have testers, or should i guess i should say.