GM Service Manual Online
For 1990-2009 cars only

PARK BRAKE Indicator Lamp Does Not Light AUTO PARK

Step

Action

Value(s)

Yes

No

1

  1. Check that the pull button switch is in the Release (pushed in) position and that the TR selector is in Park (P).
  2. Turn the ignition switch to RUN.
  3. Observe the AUTO PARK lamp on the instrument cluster.

Is the AUTO PARK lamp illuminated?

--

Go to Step 2

Go to Step 3

2

Refer to the instructions above for dealing with an intermittent problem.

Is the repair complete?

--

System OK

--

3

Observe the indicator lamps on the instrument cluster.

Is the BRAKE lamp illuminated?

--

Go to Step 4

Go to Step 6

4

  1. Turn the ignition switch to LOCK.
  2. Replace AUTO PARK Fuse 34.

Is the system performing normally?

--

System OK

Go to Step 5

5

  1. Turn the ignition switch to LOCK.
  2. Check AUTO PARK Fuse 34.

Is Fuse 34 blown again?

--

Go to Step 17

Go to Step 6

6

  1. Make sure that the Park Brake Pull Button Switch is in the Release (pushed in) position.
  2. Turn the ignition switch to RUN.
  3. Move the TR selector to Neutral (N).

Does the AUTO PARK lamp illuminate and then go off after a few seconds?

--

Go to Step 12

Go to Step 7

7

There is an open in the power feed to splice S302 through the Park Brake Pressure Indicator Switch.

  1. Disconnect the connector from the Park Brake Pressure Indicator Switch
  2. Make sure that the ignition switch is in RUN.
  3. Use a test lamp to probe from the connector terminal A to ground.

Does the test lamp illuminate?

--

Go to Step 9

Go to Step 8

8

There is an open in circuit 639 (PNK) between splice S111 and terminal A of the Park Brake Pressure Indicator Switch connector.

  1. Use a test lamp to check for power at terminal C of C300 and terminal C of C111 to isolate the portion of the circuit with the open.
  2. Locate and repair the open.

Is the repair complete?

--

System OK

--

9

Use a DMM J 39200 to check resistance across the terminals of the Park Brake Pressure Indicator Switch.

Does the resistance meet the specified value?

<2 ohms

Go to Step 11

Go to Step 10

10

Replace the Park Brake Pressure Indicator Switch.

Is the repair complete?

--

System OK

--

11

Repair the open in the circuit between the Park Brake Pressure Indicator Switch and splice S111. This includes the following circuits:

    • Circuit 907 (LT BLU) between the Park Brake Pressure Indicator Switch connector terminal B and diode splice S308
    • Diode 899A
    • Circuit 1844 (LT GRN) between diode splice S309 and splice S302

Is the repair complete?

--

System OK

--

12

The problem is in the portions of the AUTO PARK lamp circuit that are common to both switches that can turn on the lamp. They are:

    • Circuit 1844 (LT GRN) from splice S302 to the instrument cluster connector terminal 2
    • The AUTO PARK lamp
    • Circuit 451 (BLK/WHT) from the instrument cluster connector terminal 4 to ground G102
  1. Turn the ignition switch to LOCK.
  2. Set the TR selector to Park (P).
  3. Disconnect connector C202.
  4. Use a test lamp to check for voltage at terminal B3 on the IP Harness (female) end of C202.

Does the test lamp illuminate?

--

Go to Step 14

Go to Step 13

13

Repair the open in circuit 1184 (LT GRN) between terminal B3 of C202 and splice S302.

Is the repair complete?

--

System OK

--

14

Check the AUTO PARK lamp.

Is it burnt out?

--

Go to Step 15

Go to Step 16

15

Replace the AUTO PARK lamp.

Is the repair complete?

--

System OK

--

16

Repair the open in circuit 1844 (LT GRN) between terminal B3 of connector C202 and terminal 2 of the instrument cluster connector.

Is the repair complete?

--

System OK

--

17

The problem is a short to ground in one of the circuits fed from AUTO PARK Fuse 34. There are a number of these circuits and several components in different wiring harnesses. The following procedure starts at easily reached points and eliminates large portions of circuit with simple tests. When you have localized the problem area to a small portion of circuit, perform a close examination to find the short.

  1. Make sure that the TR selector is in Park (P).
  2. Open connector C300.
  3. Use a test lamp to probe terminal C of the chassis harness (female) side of C300.

Does the test lamp illuminate?

--

Go to Step 29

Go to Step 18

18

Use a test lamp to probe terminal C of the park brake harness (male) side of C300.

Does the test lamp illuminate?

--

Go to Step 19

Go to Step 22

19

Use a test lamp to probe terminal B of the park brake harness (male) side of C300.

Does the test lamp illuminate?

--

Go to Step 20

Go to Step 21

20

Locate and repair the short to ground in circuit 1844 (LT GRN) in the park brake harness between the following points:

    • Terminal B of C300 to splice S302
    • Splice S302 and diode splice S307
    • Splice S302 and diode splice S309

Is the repair complete?

--

System OK

--

21

Repair the short to ground in one of the following portions of the park brake harness:

    • Circuit 639 (PNK) between terminal C of C300 and terminal A of the Park Brake Pressure Indicator Switch connector
    • The Park Brake Pressure Indicator Switch
    • Between the Park Brake Pressure Indicator Switch and diode splice S308

Is the repair complete?

--

System OK

--

22

Use a test lamp to probe terminal B of the rear chassis harness (female) side of C300.

Does the test lamp illuminate?

--

Go to Step 23

Go to Step 24

23

Repair the short to ground in circuit 1844 (LT GRN) between terminal B of C300 and terminal 2 of the instrument cluster connector.

Is the repair complete?

--

System OK

--

24

  1. Disconnect the connector from the Park Brake Pump Motor Switch. This is standing vertically on the pump housing and has PNK/BLK and YEL/BLK wires attached.
  2. Probe terminal B with a test lamp.

Does the test lamp illuminate?

--

Go to Step 25

Go to Step 26

25

Repair the short to ground in circuit 1929 (PNK/BLK) in one of the following areas:

    • Between the Park Brake Pump Motor Switch connector terminal B and diode splice S306
    • Splice S303 and terminal 86 of the Park Brake Pump Motor Relay
    • The Park Brake Pump Motor Relay

Is the repair complete?

--

System OK

--

26

Probe terminal A of the Park Brake Pump Motor Switch connector with a test lamp.

Does the test lamp illuminate?

--

Go to Step 27

Go to Step 28

27

Repair the short to ground in circuit 1131 (YEL/BLK) in one of the following places:

    • From terminal A of the TR shift control to terminal A of the Park Brake Pump Motor Switch
    • From splice S213 to terminal C9 of the IP Wiring Harness Junction Block
    • From splice S304 to terminal A of the Park Brake Pressure Valve Solenoid
    • The Park Brake Pressure Valve Solenoid itself

Is the repair complete?

--

System OK

--

28

Replace the Park Brake Pump Motor Switch.

Is the repair complete?

--

System OK

--

29

  1. Pull the Park Brake Pull Button Switch to the Apply position.
  2. Use a test lamp to probe terminal C of the chassis harness (female) side of C300.

Does the test lamp illuminate?

--

Go to Step 31

Go to Step 30

30

Repair the short to ground in circuit 909 (YEL) in one of the following areas:

    • Between terminal B of the pull button switch and terminal F of the TR selector
    • Between splice S212 and terminal G1 of the IP Wiring Harness Junction Block (terminal 85 of the pull button relay)
    • The pull button relay
    • The pull button switch
    • The TR park switch

Is the repair complete?

--

System OK

--

31

  1. Reconnect C300.
  2. Push the pull button switch back to the Release position.
  3. Disconnect connector C111.
  4. Probe cavity C of the engine harness (female) side of C111 with a test lamp.

Does the test lamp illuminate?

--

Go to Step 33

Go to Step 32

32

Repair the short to ground in circuit 630 (PNK) in the rear chassis harness between terminal C of C111 and terminal C of C300.

Is the repair complete?

--

System OK

--

33

  1. Remove the Park Brake Alarm Relay from its socket in the Engine Wiring Harness Junction Block (Underhood Fuse Relay Center).
  2. Probe cavity C of the engine harness (female) side of C111 with a test lamp again.

Does the test lamp illuminate?

--

Go to Step 35

Go to Step 34

34

Replace the Park Brake Alarm Relay.

Is the repair complete?

--

System OK

--

35

  1. Reinstall the Park Brake Alarm Relay into its socket.
  2. Open connector C100. This requires removing the Engine Wiring Harness Junction Block (Underhood Fuse Relay Center) from its mounting.
  3. Probe cavity B2 of the engine harness (male) side of C100 with a test lamp again.

Does the test lamp illuminate?

--

Go to Step 37

Go to Step 36

36

Repair the short to ground in circuit 639 (PNK) in one of the following places:

    • Between terminal B2 of C100 and terminal A of the pull button switch
    • The Park Brake Pull Button Switch
    • Splice S203 to terminal B of the Park Brake Alarm
    • The Park Brake Alarm

Is the repair complete?

--

System OK

--

37

Repair the short to ground in circuit 639 (PNK) in one of the following places:

    • Terminal B2 of C100 to splice S111
    • Terminal C of C111 to splice S111
    • Terminal D6 of the Engine Wiring Harness Junction Block (Underhood Fuse Relay Center) to splice S111
    • Terminal J8 of the Engine Wiring Harness Junction Block (Underhood Fuse Relay Center) to splice S111

Is the repair complete?

--

System OK

--