1997 Ford F350 Owner Guide 1st Printing - Page 211

Trailer lamps Make sure your trailer lamps conform to Federal and local regulations. Your vehicle has been equipped for use with a 4-wire trailer tow electrical system (running lamps, right hand stop/turn, left hand stop/turn, and ground). Class I and Class II Trailer Tow electrical wiring provides two circuits (right hand and left hand) to operate trailer stop/turn tail lamps. Each stop/turn circuit will operate one combination stop/turn light bulb (# 1157, 3157, 2357, or 3357) on the trailer. Never add more than one trailer light bulb to one circuit. A wire harness (Ford part number F5TB-13A576-A) has been provided that connects to the frame wire harness at the rear of the vehicle and is compatible with most 4-wire trailer tow electrical systems. Always check trailer and vehicle functions (i.e., stop/turn signal, and running lights) before operating your vehicle and trailer. If your vehicle fails to function properly, do not operate your vehicle and trailer until corrections are made. RWARNING Always replace a fuse with one that has the specified amperage rating. Using a fuse with a higher amperage rating can cause severe wire damage and could start a fire. 211