This should have come with the vehicle for you to use. If it is not there, you can order a new copy from the manufacturer.
The 2002 Ford Expedition owners manual can be viewed on-line Click on the link below Click on Owner Guides
SAE 5 W 20 - certified for gasoline engines - according to the 2002 Ford Expedition owners manual
You can view the 2002 Ford Expedition owners manual online at : www . motorcraft service . com ( no spaces ) Click on Owner Guides The manual includes the fuse diagrams
Check your owners manual. If you don't have one copy & paste this link. http://www.genuineservice.com/genuineservice/en/gloveboxresults
You can view the 2000 Ford Expedition owners manual online at : www . motorcraft service . com ( no spaces ) Click on Owner Guides
You can view the 1997 Ford Expedition owners manual online at : www . motorcraft service . com ( no spaces ) Click on Owner Guides
You can view the 2004 Ford Expedition owners manual online at : www . motorcraft service . com ( no spaces ) Click on Owner Guides
The 1998 Ford Expedition owners manual shows ( 5W-30 )
Try eBay.
Owners manual will assist you
According to the owners manual - relay 203 is the Trailer Tow Backup Lamp Relay
You can view the 2002 Ford Expedition owners manual online at : www . motorcraft service . com ( no spaces ) Click on Owner Guides ( the fuses and relays section starts on page 189 )