See Figure 1
The fuse block is mounted to the firewall, inside the truck, to the left of the steering column. The turn signal flasher and hazard waring flasher plug into the fuse block. Each fuse receptacle is marked as to the circuits it protects and the correct amperage. In-line fuses are also used to protect some circuits. These are: 1972-86 ammeter, 1973-74 rear air conditioner, and 1975-86 auxiliary heater.
A special heavy duty turn signal flasher is required to properly operate the turn signals when a trailer's lights are connected to the system.