Section 17-01: Lighting, Exterior
1996 F-150, F-250, F-350, F-Super Duty Motorhome and Bronco Workshop Manual
DIAGNOSIS AND TESTING

Pinpoint Tests Headlamps

NOTE: Use Rotunda 73 Digital Multimeter 105-R0051 or equivalent when performing electrical pinpoint tests.

 

PINPOINT TEST A: HEADLAMPS INOPERATIVE

 

A1 CHECK SUPPLY VOLTAGE AT HEADLAMP SWITCH

Is battery voltage present?
YesNo
GO to A4.GO to A2.
 

A2 CHECK HEADLAMP FUSE

Is battery voltage present?
YesNo
GO to A3.SERVICE fuse 19 feed wiring or REPLACE fuse 19. RESTORE vehicle. RETEST system.
 

A3 CHECK CIRCUIT 38 (BK/O)

Is battery voltage present?
YesNo
SERVICE Circuit 38 (BK/O) for a short to ground. RESTORE vehicle. RETEST system.REPLACE damaged power distribution box fuse 19. RESTORE vehicle. RETEST system.
 

A4 CHECK HEADLAMP SWITCH OUTPUT

Is battery voltage present?
YesNo
GO to A5.REPLACE damaged headlamp switch. RESTORE vehicle. RETEST system.
 

A5 CHECK HEADLAMP INPUT TO MULTI-FUNCTION SWITCH

Is battery voltage present?
YesNo
GO to A6.SERVICE Circuit 15 (R/Y) for an open circuit. RESTORE vehicle. RETEST system.
 

A6 CHECK MULTI-FUNCTION SWITCH LOW BEAM

Is battery voltage present?
YesNo
GO to A7.REPLACE damaged multi-function switch. RESTORE vehicle. RETEST system.
 

A7 CHECK SUPPLY CIRCUIT TO HEADLAMP SWITCH

Is battery voltage present?
YesNo
GO to A8.SERVICE fuse 3 feed wiring or REPLACE fuse 3. RESTORE vehicle. RETEST system.
 

A8 CHECK CIRCUIT 196 (DB/O) FOR OPEN

Is battery voltage present?
YesNo
GO to A9.SERVICE open circuit in Circuit 196 (DB/O). RESTORE vehicle. RETEST system.
 

A9 CHECK MULTI-FUNCTION SWITCH HIGH BEAM

Is battery voltage present?
YesNo
GO to A10.REPLACE damaged multi-function switch. RESTORE vehicle. RETEST system.
 

A10 CHECK SUPPLY TO SUSPECT HEADLAMP

Is battery voltage present?
YesNo
GO to A11.SERVICE Circuit 13 (R/BK) or Circuit 12 (LG/BK) for open circuit. RESTORE vehicle. RETEST system.
 

A11 CHECK SUSPECT HEADLAMP GROUND

Is resistance 5 ohms or less?
YesNo
REPLACE damaged headlamp bulb. RESTORE vehicle. RETEST system.SERVICE Circuit 57 (BK) for open circuit. RESTORE vehicle. RETEST system.
 

PINPOINT TEST B: HEADLAMPS ON CONTINUOUSLY

 

B1 CHECK HEADLAMP SWITCH

Is battery voltage present at Pin H?
YesNo
REPLACE headlamp switch. RESTORE vehicle. RETEST system.GO to B2.
 

B2 CHECK MULTI-FUNCTION SWITCH

Is battery voltage present?
YesNo
REPLACE multi-function switch. RESTORE vehicle. RETEST system.GO to B1.
 

PINPOINT TEST C: HIGH BEAMS OR LOW BEAMS INOPERATIVE

 

C1 CHECK HEADLAMP SWITCH

Did the headlamp switch test OK?
YesNo
GO to C2 for high beam failure. GO to C4 for low beam failure.REPLACE headlamp switch. RETEST system.
 

C2 HIGH BEAMS INOPERATIVE

Is continuity present in Circuit 12 (LG/BK)?
YesNo
GO to C3.REPAIR open in Circuit 12 (LG/BK). RESTORE vehicle. RETEST system.
 

C3 CHECK CIRCUIT 57 (BK)

Is continuity present in Circuit 57 (BK)?
YesNo
REPLACE headlamp bulb. RESTORE vehicle. RETEST system.REPAIR ground circuit. RESTORE vehicle RETEST system.
 

C4 LOW BEAMS INOPERATIVE

Is continuity present?
YesNo
GO to C5.REPAIR open in Circuit 13 (R/BK). RESTORE vehicle. RETEST system.
 

C5 CHECK GROUND CIRCUIT 57 (BK)

Is continuity present?
YesNo
REPLACE headlamp bulb. RESTORE vehicle. RETEST system.REPAIR ground circuit. RESTORE vehicle. RETEST system.
 

PINPOINT TEST D: ONE HIGH BEAM OR ONE LOW BEAM HEADLAMP INOPERATIVE

 

D1 CHECK FOR POWER TO INOPERATIVE HEADLAMP

Is the voltage greater than 10 volts?
YesNo
REPLACE the headlamp bulb. RESTORE vehicle. RETEST system.SERVICE Circuit 12 (LG/BK) or Circuit 13 (R/BK) for open in the high beams or low beams. RESTORE vehicle. RETEST system.
 

PINPOINT TEST E: FLASH-TO-PASS INOPERATIVE

 

E1 FUSE CHECK

Is the fuse blown?
YesNo
REPLACE fuse 3. GO to E2.GO to E2.
 

E2 CHECK CIRCUIT 38 (BK/O)

Is continuity present?
YesNo
GO to E3.SERVICE open circuit between power distribution box and multi-function switch. REPLACE fuse. RESTORE vehicle. RETEST system.
 

E3 FLASH-TO-PASS SWITCH CHECK

Is continuity present through the multi-function switch?
YesNo
Switch OK. GO to C2.REPLACE multi-function switch. RESTORE vehicle. RETEST system.