Wondering if anyone can help out. In the process of de-winterizing my unit; went thru all the steps in the manual but water pump doesn't work. Wont turn on. All other 12 volt appliances are working

Checked fuse. Has anyone had a similar problem? Wondering if I might have done something wrong during the winterizing process?

Also...I can't even find the actual pump to check it with a voltage regulator : )