GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

Was the Brake Warning System Check performed?

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Go to Step 2

Hydraulic Brake Diagnostic System Check

2

  1. Disconnect the instrument cluster connector.
  2. Place ignition in the RUN position.
  3. Connect a J 39200 from cavity 22 of the instrument cluster connector to ground.

Is there continuity?

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Go to Step 4

Go to Step 3

3

Locate and repair the open in CKT 39 (PNK) between the instrument cluster connector and the IP fuse block. Refer to Wiring Repairs in wiring.

Is the repair complete?

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Hydraulic Brake Diagnostic System Check

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4

  1. Reconnect the instrument cluster connector.
  2. Backprobe cavity 28 of the instrument cluster connector with a fused jumper to ground.

Does the brake warning indicator light?

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Go to Step 6

Go to Step 5

5

Replace the brake warning indicator. Refer to Instrument Cluster Bulb Replacement in instrument cluster.

Is the repair complete?

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Hydraulic Brake Diagnostic System Check

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6

  1. Disconnect the daytime running lamp module (DRL) connector.
  2. Connect a fused jumper between cavity E of the DRL connector and ground.

Does the brake warning indicator light?

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Go to Step 8

Go to Step 7

7

Locate and repair open in CKT 33 (TAN/WHT) between the instrument cluster connector and the DRL connector. Refer to Wiring Repairs in wiring.

Is the repair complete?

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Hydraulic Brake Diagnostic System Check

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8

  1. Apply the parking brake.
  2. Connect a J 39200 from cavity A of the DRL connector to B+.

Is there battery voltage?

--

Go to Step 10

Go to Step 9

9

  1. Inspect for an open in CKT 1134 (LT BLU) between the DRL connector and the park brake warning switch. Refer to Wiring Repairs in wiring.
  2. If an open does not exist, replace park brake warning switch. Refer to Parking Brake Indicator Switch Replacement .

Is the repair complete?

--

Hydraulic Brake Diagnostic System Check

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10

  1. Place the ignition in the RUN position.
  2. Connect a J 39200 from cavity B of DRL connector to ground.

Is there battery voltage?

--

Go to Step 12

Go to Step 11

11

Locate and repair open in CKT 1134 (LT BLU) between G200 and C266. Refer to Wiring Repairs in wiring.

Is the repair complete?

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Hydraulic Brake Diagnostic System Check

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12

  1. Disconnect brake pressure warning switch connector.
  2. Connect a J 39200 between cavity B of brake pressure warning switch and B+.

Is there battery voltage?

--

Go to Step 14

Go to Step 13

13

Locate and repair open in CKT 150 (BLK) between the brake pressure warning switch connector and G105. Refer to Wiring Repairs in wiring.

Is the repair complete?

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Hydraulic Brake Diagnostic System Check

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14

  1. Disconnect electronic brake control module (EBCM) connector C1.
  2. Connect a J 39200 between cavity H of EBCM C1 and cavity A of brake pressure warning switch connector.

Is there continuity?

--

Go to Step 16

Go to Step 15

15

Locate and repair open in CKT 680 (PPL) between the EBCM connector and the brake pressure warning switch connector. Refer to Wiring Repairs in wiring.

Is the repair complete?

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Hydraulic Brake Diagnostic System Check

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16

Connect a J 39200 between cavity A and cavity B of brake pressure

Is there continuity?

--

Go to Step 17

Go to Step 18

17

Replace the brake pressure warning switch.

Is the repair complete?

--

Hydraulic Brake Diagnostic System Check

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18

Connect a J 39200 between cavity F of DRL connector and cavity E of EBCM connector.

Is there continuity?

--

Go to Step 20

Go to Step 19

19

Locate and repair open in CKT 33 (TAN/WHT) between the EBCM connector and the DRL connector. Refer to Wiring Repairs in wiring.

Is the repair complete?

--

Hydraulic Brake Diagnostic System Check

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20

  1. Reconnect DRL connector.
  2. Disconnect connector C100.
  3. Apply the parking brake.

Does the brake warning indicator light?

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Go to Step 21

Go to Step 22

21

Replace the electronic brake control module (EBCM). Refer to Electronic Brake Control Module Replacement .

Is the repair complete?

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Hydraulic Brake Diagnostic System Check

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22

Replace the daytime running lamp module (DRL). Refer to Daytime Running Lights (DRL) Control Module Replacement in lighting systems.

Is the repair complete?

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Hydraulic Brake Diagnostic System Check

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