GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Isuzu 🢒 2007 🢒 Isuzu MD F-Series 🢒 Body Systems 🢒 Lighting 🢒 Brake Warning Indicator Always On

Circuit Description

The instrument panel cluster (IPC) illuminates the red brake warning indicator by supplying ground to the lamp. The electronic brake control module (EBCM) sends a class 2 message to the IPC requesting illumination. The park brake switch is wired to the IPC logic. The red brake warning indicator also illuminates when the park brake is applied.

Step

Action

Yes

No

Schematic Reference: Hydraulic Brake Schematics and Instrument Cluster Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Turn OFF the ignition for 5 seconds.
  2. Ensure the park brake is released.
  3. Turn ON the ignition while observing the brake warning indicator.

Does the brake warning indicator illuminate for 3 seconds and then turn OFF?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3
  1. Install a scan tool.
  2. Select the instrument panel cluster (IPC) Special Functions menu on the scan tool.
  3. Command all of the IPC indicators lamps OFF.

Does the brake warning indicator turn OFF?

Go to Step 4

Go to Step 8

4
  1. Disconnect the scan tool.
  2. Disconnect the park brake switch harness connector.

Does the brake warning indicator turn OFF?

Go to Step 6

Go to Step 5

5
  1. Select the Hydraulic 4WAL 4 Sensor Data List on the scan tool.
  2. Observe the Brake Warning Lamp Command status.

Does the scan tool display On?

Go to Step 9

Go to Step 7

6

Replace the park brake switch. Refer to Parking Brake Indicator Switch Replacement .

Did you complete the replacement?

Go to Step 10

--

7
  1. Remove the IPC. Refer to Instrument Cluster Replacement .
  2. Test the park brake switch output circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 10

Go to Step 8

8

Replace the IPC. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 10

--

9

Replace the electronic brake control module (EBCM). Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 10

--

10
  1. Turn OFF the ignition for 5 seconds.
  2. Ensure the park brake is released.
  3. Turn ON the ignition while observing the brake warning indicator.

Does the brake warning indicator illuminate for 3 seconds and then turn OFF?

System OK

Go to Step 3