Late Model Ford Truck Tech Tips

So you want to add some electrical accessories to your new truck...
(a guide to 1997 Ford F-150 Electrical Systems)
Contributed by Nic Colasurdo
Appendix A - Types of Switches
SPST Switch

"Closed" circuit (ON)

"Open" circuit (OFF)
SPDT Switch

Circuit B - "Closed" (ON)
Circuit A - "Open" (OFF)

Circuit A - "Closed" (ON)
Circuit B - "Open" (OFF)
SPDT SWITCH (CENTER-OFF)

Both A & B circuits are "OPEN" (Both are OFF)
DPST SWITCH

Circuits A & B are both "OPEN"
(both circuits are OFF)

Circuits A & B are both "Closed"
(both circuits are ON)
DPDT SWITCH

Circuits B & D - "Closed" (ON)
Circuits A & C - "Open" (OFF)

Circuits A & C - "Closed" (ON)
Circuits B & D - "Open" (OFF)
DPDT SWITCH (CENTER-OFF)

All four circuits are "OPEN" (OFF)

On to Appendix B...