Ford 2002 F650 Owner's Manual page 159

Relays
The relay box is located on the rear crossmember.
Air Brake Trailer Tow Relays (if equipped)
The relays are coded as follows:
Fuse/Relay
Location
1
2
3
4
5
R1
R2
R3
R4
R5
R6
R7
R8
** Maxi Fuse
Fuse Amp
Rating
30A** Trailer Tow Run Feed
30A** Trailer Tow Park/Marker Lamps
30A** Trailer Tow Stop Lamps
30A** Trailer Tow Turn/Stop Lamps
— Not Used
— Trailer Tow Run Relay
— Trailer Tow Stop Lamp relay
— Trailer Tow Park/Marker Lamp Relay
— Trailer Tow Park/Marker Lamp Relay
— Not Used
— Not Used
— Trailer Tow Left Turn/Stop Lamp Relay
— Trailer Tow Right Turn/Stop Lamp Relay
Roadside Emergencies
Description
159