1996 Bronco/F-Series

Section 01-14A: Handles, Locks, Latches and Mechanisms

1996 F-150, F-250, F-350, F-Super Duty and Bronco Workshop Manual

DIAGNOSIS AND TESTING

Pinpoint Tests

PINPOINT TEST A: ONE DOOR LOCK INOPERATIVE

A1 CHECK OPERATION OF SUSPECT DOOR LOCK

Manually operate inoperative door lock.
Check for binding or stuck condition.

Is lock stuck or binding?

Yes	No
REFER to Lock CylinderLubricant in the Lubrication portion of this section. SERVICE as required.	GO to A2.

A2 CHECK SUSPECT POWER DOOR LOCK ACTUATOR LOCK OPERATION

Gain access to suspect power door lock actuator. Refer to Actuator, Power Door Lock, in the Removal and Installation portion of this section.
Disconnect power door lock actuator.
Using a test lamp connected to a known good ground, check Circuit 117 (PK/BK) at harness connector while actuating door locks in the lock position.

Did test lamp illuminate?

Yes	No
GO to A3.	SERVICE Circuit 117 (PK/BK) for open circuit. RETEST system.

A3 CHECK POWER DOOR LOCK ACTUATOR FOR UNLOCK OPERATION

Remove test lamp from Circuit 117 (PK/BK) and connect it to Circuit 118 (PK/O).
Actuate switch in the unlock position.

Did test lamp illuminate?

Yes	No
GO to A4.	SERVICE Circuit 118 (PK/O) for open circuit. RETEST system.

A4 CHECK POWER DOOR LOCK ACTUATOR

Using two 10 gauge jumper wires connected to battery positive (+) and negative (-), attach jumpers to actuator connector; reverse polarity for opposite direction.

Did actuator operate correctly?

Yes	No
GO to A5.	REPLACE power door lock actuator. RETEST system.

A5 CHECK POWER DOOR LOCK ACTUATOR CURRENT DRAW

Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent, check actuator current draw.

Is current draw 6 amps or less?

Yes	No
Actuator OK. RECONNECT power door lock actuator.	REPLACE power door lock actuator. RETEST system.

PINPOINT TEST B: ALL DOOR LOCKS INOPERATIVE

B1 CHECK SUPPLY TO LOCK SWITCH

Partially remove left door lock switch.
Using voltmeter, check Circuit 171 (BK/W), Pin 3 at switch connector for voltage.

Is battery voltage present?

Yes	No
GO to B4.	GO to B2.

B2 CHECK CIRCUIT 171 (BK/W) FOR OPEN

Disconnect circuit breaker (20A) at primary junction block.
Disconnect left door lock switch.
Using an ohmmeter, check resistance of Circuit 171 (BK/W) from door lock switch connector to output side of SEAT/LOCK circuit breaker (20A) cavity.

Is resistance 5 ohms or less?

Yes	No
GO to B3.	SERVICE Circuit 171 (BK/W) for open. RETEST system.

B3 CHECK CIRCUIT 171 (BK/W) FOR SHORT

Using ohmmeter connected to a known good ground, connect second lead to Circuit 171 (BK/W) at door lock switch connector.
Measure resistance.

Is resistance 5 ohms or less?

Yes	No
SERVICE Circuit 171 (BK/W) for short. RETEST system.	REPLACE circuit breaker (20A). RETEST system.

B4 CHECK CIRCUIT 57 (BK)

Using an ohmmeter connected to a known good ground, connect second lead to Circuit 57 (BK), Pins 1 and 5 at door lock switch connector.
Measure resistance.

Is resistance 5 ohms or less?

Yes	No
GO to B5.	SERVICE Circuit 57 (BK) for open. RETEST system.

B5 CHECK DOOR LOCK SWITCH LOCK OUTPUT

Partially remove RH door lock switch.
Using a voltmeter, check Circuit 117 (PK/BK) at switch connector Pin 4 for voltage as switch is actuated to the lock position.

Is battery voltage present?

Yes	No
GO to B6.	REPLACE RH door lock switch. RETEST system.

B6 CHECK DOOR LOCK SWITCH UNLOCK OUTPUT

Disconnect voltmeter lead from Circuit 117 (PK/BK).
Connect lead to Circuit 118 (PK/O), Pin 2 at switch connector.
Measure voltage as switch is actuated to unlock position.

Is battery voltage present?

Yes	No
GO to B7.	REPLACE RH door lock switch. RETEST system.

B7 CHECK CIRCUIT 117 (PK/BK)

Gain access to RH door lock actuator. Refer to Actuator, Power Door Lock, in the Removal and Installation portion of this section.
Disconnect door lock actuator.
Using a test lamp, check for voltage at Circuit 117 (PK/BK) in harness connector as switch is actuated to the lock position.

Did test lamp illuminate?

Yes	No
SERVICE Circuit 118 (PK/O) for open circuit. RETEST system.	SERVICE Circuit 117 (PK/BK) for open circuit. RETEST system.

PINPOINT TEST C: ALL LOCKS WORK FROM ONE SWITCH ONLY

C1 CHECK SUSPECT SWITCH

Remove suspect switch.
Perform switch test. Refer to Door Lock Switch under Component Tests in the Diagnostic and Testing portion of this section.

Did switch test OK?

Yes	No
GO to C2.	REPLACE door lock switch. RETEST system.

C2 CHECK SUPPLY TO SWITCH

Using a test lamp, check Circuit 171 (BK/W) at Pin 3 for LH switch or Pin 3 for RH switch for voltage.

Did test lamp illuminate?

Yes	No
GO to C3.	SERVICE Circuit 171 (BK/W) for open. RETEST system.

C3 CHECK CIRCUIT 119 (PK/Y)

Remove opposite door lock switch.
Using an ohmmeter, check Circuit 119 (PK/Y) from Pin 2 at LH door lock switch connector to Pin 5 at RH door lock switch connector for continuity.

Is continuity present?

Yes	No
GO to C4.	SERVICE Circuit 119 (PK/Y) for open. RETEST system.

C4 CHECK CIRCUIT 120 (PK/LG)

Using ohmmeter, check Circuit 120 (PK/LG) from Pin 4 at LH door lock switch connector to Pin 1 at RH door lock switch connector for continuity.

Is continuity present?

Yes	No
REPLACE opposite door lock switch. RETEST system.	SERVICE Circuit 120 (PK/LG) for open. RETEST system.

PINPOINT TEST D: DOOR LOCKS OPERATE ONE WAY ONLY

D1 CHECK LOCK OPERATION

Actuate either power door lock switch to the lock position.

Did the doors lock?

Yes	No
GO to D2.	GO to D5.

D2 CHECK CIRCUIT 118 (PK/O) FOR SHORT TO GROUND

Disconnect RH door lock switch.
Using Rotunda 73 Digital Multimeter 105-R0051 or equivalent, check for continuity between Circuit 118 (PK/O) and known good ground.

Is continuity present?

Yes	No
SERVICE Circuit 118 (PK/O) for short to ground. RETEST system.	GO to D3.

D3 CHECK CIRCUIT 120 (PK/LG) FOR SHORT TO GROUND

Leaving RH door lock switch disconnected, disconnect LH door lock switch.
Using multimeter, check for continuity between Circuit 120 (PK/LG) and known good ground.

Is continuity present?

Yes	No
SERVICE Circuit 120 (PK/LG) for short to ground. RETEST system.	GO to D4.

D4 CHECK CIRCUIT 57 (BK) FOR CONTINUITY

Using multimeter, check for continuity at LH door lock switch connector between Circuit 57 (BK), Pins 1 and 5, and known good ground.

Is continuity present?

Yes	No
REPLACE LH door lock switch. RETEST system.	SERVICE Circuit 57 (BK) for open. RETEST system.

D5 CHECK CIRCUIT 117 (PK/BK) FOR SHORT TO GROUND

Perform Step D2, substituting Circuit 117 (PK/BK) for Circuit 118 (PK/O).

Is continuity present?

Yes	No
SERVICE Circuit 117 (PK/BK) for short to ground. RETEST system.	GO to D6.

D6 CHECK CIRCUIT 119 (PK/Y) FOR SHORT TO GROUND

Perform Step D3, substituting Circuit 119 (PK/Y) for Circuit 120 (PK/LG).

Is continuity present?

Yes	No
SERVICE Circuit 119 (PK/Y) for short to ground. RETEST system.	GO to D4.

PINPOINT TEST E: DOOR LOCKS WORK WITH ENGINE RUNNING ONLY

E1 CHECK SUPPLY CIRCUIT

Using a voltmeter, check vehicle battery voltage.

Is voltage 10 volts or more?

Yes	No
GO to E2.	REFER to Section 14-01 for proper service.

E2 CHECK LATCH/LINKAGE

Manually lock/unlock door.

Does latch operate easily?

Yes	No
GO to E3.	REFER to Lock Cylinder Lubricant in the Lubrication portion of this section and SERVICE as necessary.

E3 CHECK DOOR LOCK SWITCH CONNECTOR

Partially remove left door lock switch. Refer to Control Switch, Door Lock, in the Removal and Installation portion of this section.
Inspect connector for corrosion or damaged/loose connection.

Is connector OK?

Yes	No
REFER to Lock Cylinder Lubricant in the Lubrication portion of this section and SERVICE as necessary. RETEST system.	SERVICE as required. RETEST system.

PINPOINT TEST F: DOOR LOCKS WORK INTERMITTENTLY

F1 CHECK CONNECTORS

Access lock switches.
Check connectors for corrosion and tightness.

Are connectors OK?

Yes	No
GO to F2.	SERVICE as required. RETEST system.

F2 CHECK GROUND CIRCUIT AT RH SWITCH

Using an ohmmeter connected to a known good ground, connect second lead to Circuit 57 (BK) at Pin 1 and Pin 5 on left door lock switch connector.
Measure resistance of each circuit.

Is resistance 5 ohms or less?

Yes	No
REFER to Door Lock Switch under Component Tests in the Diagnosis and Testing portion of this section. SERVICE as required.	SERVICE Circuit 57 (BK) for open circuit. RETEST system.