Re: Code P1633 on '01 Expedition
Fuse locations 2,6,7,8,15,18,20,27 & 29 are the 5A fuse locations in the passenger compartment fuse box.
There seems to be a common problem of leaking windshield dropping water in the top of the fusebox on the GEM Module. This could be a possibility. If you do a web search on GEM Module for the 2000-2001 Exp. you'll see what I mean.