Caution: Chock the wheels to prevent the vehicle from moving. Failure to chock the wheels can cause personal injury when the electrical system is repaired.

1. Turn the ignition to RUN.
2. Observe the instrument cluster.

Is the AUTO PARK lamp illuminated?

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Go to Step 2

Go to Step 6

1. Continue to observe the AUTO PARK lamp.
2. Move the transmission range (TR) selector out of the PARK position.

Does the AUTO PARK lamp turn off after a few seconds?

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Go to Step 3

Go to Step 12

1. Position yourself where you can see the park brake mechanism.
2. Have an assistant move the transmission rance selector between Park and Neutral with the ignition in RUN.

Does the mechanism move at all as the brake is applied and released?

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Go to Step 4

Go to Step 5

Examine the parking brake for a mechanical problem that is preventing its release and repair as required.

Is the repair complete?

--

System OK

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Replace the park brake actuator. Parking Brake Actuator Replacement

Is the repair complete?

--

System OK

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1. Turn the ignition switch to LOCK.
2. Inspect AUTO APPLY fuse 19.

Has the fuse blown?

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Go to Step 8

Go to Step 7

Locate and repair the open in CKT 639 (PNK) between AUTO APPLY fuse 19 (fuse block terminal B6) and splice S212.

Is the repair complete?

--

System OK

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1. Replace AUTO APPLY fuse 19.
2. Turn the ignition to RUN.

Does the fuse blow again?

--

Go to Step 9

Go to Step 10

1. Locate the short to ground in one of the following locations:

•	CKT 639 (PNK) from the AUTO APPLY fuse 19 (fuse block terminal B6) to splice S212

-	from S212 to the park brake alarm

-	from S212 to the park brake alarm relay

-	from S212 to terminal F4 of C200

•	From terminal F4 of C200 to splice S169

-	from S169 to the pull button switch

-	from S169 to the park/neutral position and backup lamps switch

-	from S169 to the park brake pressure indicator switch

•	CKT 909 (DK GRN) from the pull button switch to splice S230 (S109 Diesel)

-	from S230 (S190 Diesel) to the park/neutral position switch relay

-	from S230 (S190 Diesel) to the park brake pull button relay

•	CKT 1737 (YEL) from terminal B, Connector C1 of the park/neutral position and backup lamps switch to splice S231

-	from S231 to the park/neutral position switch relay

-	from S231 to the BTSI relay

-	from S231 to the upfitter connector

2. Repair as required.

Is the repair complete?

--

System OK

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Move the TR selector out of Park.

Does the park brake release normally?

--

System OK

Go to Step 11

Check AUTO APPLY fuse 19.

Did the fuse blow again?

--

Go to Step 12

Go to Step 13

1. Locate the short to ground in one of the following locations:

•	CKT 1131 (YEL/BLK) from the park/neutral position switch relay to splice S361

-	S361 to the pressure valve solenoid

-	S361 to the pump motor switch

•	The pressure valve solenoid

•	The pump motor switch

•	CKT 1929 (PNK/BLK) from the pump motor switch to splice S363

-	S363 to splice S301 at diode D301

-	S363 to the pump motor relay

•	The pump motor relay

2. Repair as required

Is the repair complete?

--

System OK

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1. Return the TR selector to Park.
2. Examine the park brake pump hydraulic fluid reservoir.

Is the fluid level low?

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Go to Step 14

Go to Step 16

1. Fill the reservoir to the proper level with Dextron III transmission fluid. Refer to Checking and Adding Park Brake Fluid
2. Examine the hydraulic components for signs of a leak.

Is there any indication of a hydraulic leak?

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Go to Step 15

Go to Step 16

Repair the park brake hydraulic system as required.

Is the repair complete?

--

System OK

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1. Position yourself near the hydraulic pump.
2. Have an assistant move the TR selector out of Park with the ignition in RUN.

Does the pump motor operate?

--

Go to Step 17

Go to Step 20

Examine the system for any indication of a leak under pressure.

Is there a leak?

--

Go to Step 15

Go to Step 18

Check the functioning of the system.

Does the park brake release properly?

--

System OK

Go to Step 19

1. Examine the following components for a problem:

•	An open in CKT 1131 (YEL/BLK) from S361 to terminal A of the pressure valve solenoid

•	An open in CKT 150 (BLK) form S364 to terminal B of the pressure valve solenoid

•	A malfunction of the pressure valve solenoid

2. Repair/replace as required.

Is the repair complete?

Less than 1 ohms

System OK

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1. Move the TR to Park.
2. Disconnect the park brake pump motor.
3. Use a J 39200 to check for continuity to ground from connector terminal B, CKT 150 (BLK).

Is the resistance as specified?

--

Go to Step 22

Go to Step 21

Repair CKT 150 (BLK) between pump motor connector terminal B to ground G350.

Is the repair complete?

--

System OK

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1. Connect the J 39200 between the terminals of the pump motor connector.
2. Set the meter for DC volts.
3. Move the TR selector out of Park with the ignition in RUN.

Does the DVM indicate the specified voltage?

11-14 v

Go to Step 23

Go to Step 24

Replace the park brake pump.

Is the repair complete?

--

System OK

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1. Move the TR to park.
2. Turn the ignition to LOCK.
3. Remove the pump motor relay connector from the relay.
4. Use a J 39200 to check for continuity in CKT 1470 (ORN) between the relay socket terminal 87 and the pump motor connector terminal A.

Is the resistance within the specified limit?

Less than 1 ohms

Go to Step 26

Go to Step 25

Repair the open in CKT 1470 (ORN).

Is the repair complete?

--

System OK

--

Replace the park brake pump motor relay.

Is the repair complete?

11-14 v

Go to Step 28

Go to Step 27

Repair the open in CKT 2 (RED).

Is the repair complete?

System OK

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1. Turn the ignition to RUN.
2. Move the TR out of Park.
3. Use a J 39200 to measure voltage in CKT 1929 (PNK/BLK) between pump motor relay socked terminal 86 and ground.

Is the voltage within specified limits?

11-14 v

Go to Step 29

Go to Step 32

Use a J 39200 to check continuity in CKT 150 (BLK) ) between the pump motor relay terminal 85 and ground G350.

Is the resistance as specified?

Less than 1 ohms

Go to Step 30

Go to Step 31

Replace the pump motor relay.

Is the repair complete?

--

System OK

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Repair the open in CKT 150 (BLK).

Is the repair complete?

--

System OK

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1. Disconnect the pump motor switch (CKT 1929 (PNK/BLK) and CKT 1131 (YEL/BLK)).
2. Use a J 39200 to measure voltage between the pump motor switch connector terminal A (YEL/BLK) and ground with the ignition in RUN and the TR out of Park.

Is the voltage as specified?

11-14 v

Go to Step 33

Go to Step 36

Use a J 39200 to measure resistance between the pump motor switch terminals.

Is the resistance as specified?

Less than 1 ohms

Go to Step 34

Go to Step 35

1. Locate the open in CKT 1929 (PNK/BLK) between the pump motor switch and the pump motor relay.
2. Repair the open as required.

Is the repair complete?

--

System OK

--

Replace the pump motor switch.

Is the repair complete?

--

System OK

--

With the ignition in RUN and the TR out of Park, measure voltage between terminal A of connector C104 and ground.

Is the voltage as specified?

11-14 v

Go to Step 37

Go to Step 38

Locate the open in CKT 1131 (YEL/BLK) between terminal A of connector C104 and the pump motor switch terminal A.

Is the repair complete?

--

System OK

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1. Remove the park/neutral position switch relay from its socket.
2. With the ignition in RUN, use a J 39200 to measure voltage between terminal 30 of the relay socket and ground.

Does the voltage within the specified range?

11-14 v

Go to Step 40

Go to Step 39

1. Locate the open in one of the following areas:

•	CKT 909 (DK GRN) between the park/neutral position switch relay terminal 30 and park brake pull button switch

•	CKT 639 (PNK) between the pull button switch and splice S169

•	Check the pull button switch for proper functioning

2. Repair the open or replace the switch as required.

Is the repair complete?

--

System OK

--

Use a J 39200 to measure resistance between terminal 30 and terminal 87A of the park/neutral position switch relay.

Is the resistance as specified?

Less than 1 ohms

Go to Step 42

Go to Step 41

Replace the park/neutral position switch relay.

Is the repair complete?

--

System OK

--

With the ignition in RUN and the TR out of Park, use a J 39200 to measure voltage between the park/neutral position switch relay terminal 85 and ground.

Is the voltage as specified?

11-14 v

Go to Step 44

Go to Step 43

Locate and repair the open in CKT 1131 (YEL/BLK) between the park/neutral position switch relay terminal 87A and terminal A of C104.

Is the repair complete?

--

System OK

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1. Disconnect connector C1 (7 GRY) from the park/neutral position and backup lamps switch.
2. With the ignition in RUN and the TR selector out of Park, use a J 39200 to measure voltage between terminal B of connector C1 and ground.

Is the voltage as specified?

11-14 v

Go to Step 46

Go to Step 45

Replace the park/neutral position and backup lamps switch.

Is the repair complete?

--

System OK

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1. Locate the short to B+ in CKT 1737 (YEL) in one of the following areas:

•	Terminal B of the park/neutral position and backup lamps switch and park/neutral position switch relay terminal 85

•	Splice S231 and the BTSI relay terminal 85

•	S231 and the upfitter connector

2. Repair as required.

Is the repair complete?

--

System OK

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1. Turn the ignition switch to the LOCK position.
2. Have an assistant check the pump.

Is the park brake pump motor running?

--

Go to Step 2

Go to Step 7

Inspect the instrument cluster.

Is the AUTO PARK lamp illuminated?

--

Go to Step 3

Go to Step 4

Repair a short to B+ in one of the following areas:

Is the repair complete?

--

System OK

--

Disconnect the pump motor relay.

Is the pump still running?

--

Go to Step 5

Go to Step 6

Repair a short to B+ in CKT 1470 (ORN) between the park brake pump motor relay and the park brake pump motor.

Is the repair complete?

--

System OK

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Replace the park brake pump motor relay. Refer to Park Brake Pressure Relay Replacement .

Is the repair complete?

--

System OK

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1. Ensure that the pull button switch is pushed in.
2. Ensure that the transmission range (TR) selector is in Park.
3. Turn the ignition switch to the RUN position.

Is the pump running?

--

Go to Step 3

Go to Step 8

Inspect the hydraulic fluid reservoir of the park brake pump.

Is the reservoir empty?

--

Go to Step 9

Go to Step 13

1. Fill the pump reservoir with Dextron III. Refer to Checking and Adding Park Brake Fluid .
2. With the ignition in RUN, move the TR selector out of Park.

Is there a visible leak when the pump is running?

--

Go to Step 10

Go to Step 11

Repair the leak.

Is the repair complete?

--

System OK

--

Inspect the reservoir.

Is the reservoir empty again?

--

Go to Step 12

Go to Step 13

Replace the actuator assembly. Refer to Parking Brake Actuator Replacement .

Is the repair complete?

--

System OK

--

Disconnect the pump motor switch.

Is the pump still running?

--

Go to Step 3

Go to Step 14

Locate and replace the failed hydraulic component:

Is the repair complete?

--

System OK

--

Turn the ignition to the LOCK position.

Is the park brake released?

--

Go to Step 2

Go to Step 7

Inspect the instrument cluster.

Is the BRAKE lamp illuminated?

--

Go to Step 3

Go to Step 4

1. Inspect for a mechanical problem in one of the following areas:

•	The park brake cable. Refer to Park Brake Cable Inspection .

•	The park brake shoes. Refer to Parking Brake Shoe Inspection .

2. Adjust, repair, or replace any components as required.

Is the repair complete?

--

System OK

--

Disconnect the pump motor switch.

Does the park brake apply?

--

Go to Step 5

Go to Step 6

Repair the short to B+ in CKT 1131 (YEL/BLK).

Is the repair complete?

--

System OK

--

Find and repair the mechanical problem in the brake, cable, or linkage.

Is the repair complete?

--

System OK

--

1. Turn the ignition switch to the RUN position.
2. Ensure that the transmission range (TR) selector is in Park.
3. Pull the pull button switch.

Does the brake apply?

--

Go to Step 8

Go to Step 9

1. Inspect for a problem in one of the following areas:

•	A failed PNP relay

•	A failed PNP switch

•	An open in one of the following circuits:

-	CKT 639 (PNK) between splice S169 and the PNP switch

-	CKT 1737 (YEL) between the PNP switch and the PNP relay

-	CKT 150 (BLK) between the PNP relay and splice S135

2. Repair or replace any component as required.

Is the repair complete?

--

System OK

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Find and repair a short to the switched ignition in CKT 1131 (YEL/BLK)

Is the repair complete?

--

System OK

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