1996 Bronco/F-Series

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

Gain access to the headlamp switch connector.
Using a voltmeter connected to a known good ground, check for battery voltage at Pin B1 of headlamp switch.

Is battery voltage present?

Yes	No
GO to A4.	GO to A2.

A2 CHECK HEADLAMP FUSE

Using a Rotunda 73 Digital Multimeter, check output voltage at power distribution box fuse 19, 40A.

Is battery voltage present?

Yes	No
GO to A3.	SERVICE fuse 19 feed wiring or REPLACE fuse 19. RESTORE vehicle. RETEST system.

A3 CHECK CIRCUIT 38 (BK/O)

Using a voltmeter, check for battery voltage on Circuit 38 (BK/O) at fuse 19 and at headlamp switch.

Is battery voltage present?

Yes	No
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

Actuate the headlamp switch to the HEAD position.
Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent connected to a known good ground, check Pin H, Circuit 15 (R/Y) at headlamp switch for voltage.

Is battery voltage present?

Yes	No
GO to A5.	REPLACE damaged headlamp switch. RESTORE vehicle. RETEST system.

A5 CHECK HEADLAMP INPUT TO MULTI-FUNCTION SWITCH

Headlamp switch still in the HEAD position.
Gain access to the multi-function switch connector.
Using Rotunda 73 Digital Multimeter connected to a known good ground, check Pin C2-2, Circuit 15 (R/Y) at multi-function switch.

Is battery voltage present?

Yes	No
GO to A6.	SERVICE Circuit 15 (R/Y) for an open circuit. RESTORE vehicle. RETEST system.

A6 CHECK MULTI-FUNCTION SWITCH LOW BEAM

Headlamps in LO beam position.
Rotunda 73 Digital Multimeter still connected to a known good ground, check Pin C2-3, Circuit 13 (R/BK) at multi-function switch connector for battery voltage.

Is battery voltage present?

Yes	No
GO to A7.	REPLACE damaged multi-function switch. RESTORE vehicle. RETEST system.

A7 CHECK SUPPLY CIRCUIT TO HEADLAMP SWITCH

Using Rotunda 73 Digital Multimeter connected to a known good ground, check Circuit 38 (BK/O) at output side of 30A fuse 3 in power distribution box.

Is battery voltage present?

Yes	No
GO to A8.	SERVICE fuse 3 feed wiring or REPLACE fuse 3. RESTORE vehicle. RETEST system.

A8 CHECK CIRCUIT 196 (DB/O) FOR OPEN

Using a Rotunda 73 Digital Multimeter 105-R0051 or equivalent, check for battery voltage on Circuit 196 (DB/O) at multi-function switch connector Pin C2-7.

Is battery voltage present?

Yes	No
GO to A9.	SERVICE open circuit in Circuit 196 (DB/O). RESTORE vehicle. RETEST system.

A9 CHECK MULTI-FUNCTION SWITCH HIGH BEAM

Headlamps in HI beam position.
Rotunda 73 Digital Multimeter 105-R0051 or equivalent still connected to a known good ground, check Pin C2-5, Circuit 12 (LG/BK) at multi-function switch connector for battery voltage.

Is battery voltage present?

Yes	No
GO to A10.	REPLACE damaged multi-function switch. RESTORE vehicle. RETEST system.

A10 CHECK SUPPLY TO SUSPECT HEADLAMP

Gain access to the suspect headlamp connector. Disconnect the suspect headlamp connector.
Actuate headlamp switch to the HEAD position.
Using Rotunda 73 Digital Multimeter connected to a known good ground, connect other end to Circuit 13 (R/BK) for low beam test and Circuit 12 (LB/BK) for high beam test. Check for voltage with multi-function switch in LO beam or HI beam position.

Is battery voltage present?

Yes	No
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

Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent connected to a known good ground, connect second lead to Circuit 57 (BK) at headlamp connector.
Measure resistance.

Is resistance 5 ohms or less?

Yes	No
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

With headlamp switch in the OFF position, use Rotunda 73 Digital Multimeter 105-R0051 or equivalent to check for voltage at Pin H of the headlamp switch.

Is battery voltage present at Pin H?

Yes	No
REPLACE headlamp switch. RESTORE vehicle. RETEST system.	GO to B2.

B2 CHECK MULTI-FUNCTION SWITCH

With headlamp switch in the OFF position, check for voltage at Circuit 12 (LG/BK) and Circuit 13 (R/BK) on the multi-function switch.

Is battery voltage present?

Yes	No
REPLACE multi-function switch. RESTORE vehicle. RETEST system.	GO to B1.

PINPOINT TEST C: HIGH BEAMS OR LOW BEAMS INOPERATIVE

C1 CHECK HEADLAMP SWITCH

Perform the headlamp switch component test. Refer to Component Tests in this section.

Did the headlamp switch test OK?

Yes	No
GO to C2 for high beam failure. GO to C4 for low beam failure.	REPLACE headlamp switch. RETEST system.

C2 HIGH BEAMS INOPERATIVE

With headlamp switch in the OFF position, use Rotunda 73 Digital Multimeter 105-R0051 or equivalent to check Circuit 12 (LG/BK) at the left and the right headlamp connector to Circuit 12 (LG/BK) at the multi-function switch.

Is continuity present in Circuit 12 (LG/BK)?

Yes	No
GO to C3.	REPAIR open in Circuit 12 (LG/BK). RESTORE vehicle. RETEST system.

C3 CHECK CIRCUIT 57 (BK)

With headlamp switch in the OFF position, use Rotunda 73 Digital Multimeter 105-R0051 or equivalent to check Circuit 57 (BK) from ground to the headlamp connector.

Is continuity present in Circuit 57 (BK)?

Yes	No
REPLACE headlamp bulb. RESTORE vehicle. RETEST system.	REPAIR ground circuit. RESTORE vehicle RETEST system.

C4 LOW BEAMS INOPERATIVE

With headlamp switch in the OFF position, use Rotunda 73 Digital Multimeter 105-R0051 or equivalent to check Circuit 13 (R/BK) at the left and the right headlamp connector to Circuit 13 (R/BK) at the multi-function switch.

Is continuity present?

Yes	No
GO to C5.	REPAIR open in Circuit 13 (R/BK). RESTORE vehicle. RETEST system.

C5 CHECK GROUND CIRCUIT 57 (BK)

With headlamp switch in OFF position, use Rotunda 73 Digital Multimeter 105-R0051 or equivalent to check Circuit 57 (BK) from the ground to the headlamp connector.

Is continuity present?

Yes	No
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

Disconnect connector to inoperative headlamp.
Headlamp switch in the HEAD position.
For high beams inoperative:

High beams on.
Measure the voltage on Circuit 12 (LG/BK) at the headlamp connector.

For low beams inoperative:

Low beams on.
Measure the voltage on Circuit 13 (R/BK) at the headlamp connector.

Is the voltage greater than 10 volts?

Yes	No
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

Check power distribution box fuse 3.

Is the fuse blown?

Yes	No
REPLACE fuse 3. GO to E2.	GO to E2.

E2 CHECK CIRCUIT 38 (BK/O)

Remove fuse 3.
Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent, check continuity on Circuit 38 (BK/O) from power distribution box to multi-function switch connector at Circuit 196 (DB/O).

Is continuity present?

Yes	No
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

Remove fuse 3.
With the flash-to-pass switch held in the ON position, use Rotunda 73 Digital Multimeter 105-R0051 or equivalent to measure continuity from Circuit 196 (DB/O) at the multi-function switch to Circuit 12 (LG/BK) of the multi-function switch.

Is continuity present through the multi-function switch?

Yes	No
Switch OK. GO to C2.	REPLACE multi-function switch. RESTORE vehicle. RETEST system.