D 250 Pickup V8-360 5.9L VIN 5 (1989)
Door Lock Switch: Testing and Inspection
Door Lock Switch Continuity
Remove the switch from its mounting location and disconnect the wires from the back of the switch. Connect a test light between the black wire and the
red wire. If the test light comes on bright, the power and ground sources for the right switch are sufficient. If the light does not come on or is dim, then
check the circuit breaker and wiring. Using an ohmmeter, check the switch for continuity between the indicated pins in both the lock and unlock
positions. If the continuity is incorrect, replace the switch.