Test Description
The numbers below refer to the step numbers on the diagnostic table.
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When the ignition is turned ON, the brake lamp should initially illuminate and then dim for ABS equipped vehicles. This is done as a bulb check. On vehicles that are not equipped with ABS, the brake warming lamp should only illuminate when either the brake fluid reservoir is low or the parking is applied.
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The brake fluid level switch is a normally open switch. If the BRAKE warning lamp is OFF after disconnecting the switch, the brake fluid level switch is stuck closed.
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If the BRAKE warning lamp is still on after disconnecting the parking brake switch, there is a short to ground in the wire to the parking brake switch.
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If the other checks have been properly performed and the BRAKE warning lamp is OFF after disconnecting the electronic brake control module (EBCM) connector, the EBCM is faulty.
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If the BRAKE warning lamp dose not operate while performing any of the functions, the fault should be in the ignition feed to the circuit.
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This step determines if the problem is in the ignition feed to the circuit or in the instrument cluster.
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The BRAKE warning lamp should illuminate when the parking brake connector is jumped to ground.
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If the BRAKE warning lamp is on after the brake fluid level switch terminals have been jumped, the switch is faulty.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Start the engine and leave it running. Is the BRAKE warning lamp always on? | -- | Go to Step 2 | Go to Step 18 |
2 | Check the ABS warning Lamp. Is the ABS warning lamp also on? | -- | Go to Step 3 | Go to Step 4 |
3 | Use a scan tool to check for diagnostic trouble codes (DTCs) and follow the procedures for any DTCs found. Were any DTC(s) stored current or history? | -- | Go to the table the (DTCs) | Go to Step 4 |
4 | Release the parking brake fully. Is the BRAKE warning lamp off? | -- | System OK | Go to Step 5 |
5 | Check the brake fluid level. Is the fluid level OK? | -- | Go to Step 7 | Go to Step 6 |
6 |
Is the BRAKE warning lamp on? | -- | Go to Step 7 | System OK |
7 | Disconnect the wiring harness connector from the brake fluid level switch. Is the BRAKE warning lamp on? | -- | Go to Step 9 | Go to Step 8 |
8 | Replace the brake fluid lever switch. Is the repair complete? | -- | System OK | -- |
9 |
Is the BRAKE warning lamp on? | -- | Go to Step 11 | Go to Step 10 |
10 | Replace the parking brake switch. Is the repair complete? | -- | System OK | -- |
11 | Connect the parking brake switch. Is the vehicle equipped with ABS? | -- | Go to Step 12 | Go to Step 14 |
12 |
Is the BRAKE warning lamp on? | -- | Go to Step 14 | Go to Step 13 |
13 | Replace the EBCM. Is the repair complete? | -- | System OK | -- |
14 |
Is the problem found? | -- | Go to Step 17 | Go to Step 15 |
15 | Check for a short to ground in the wiring between the instrument cluster terminal B9 and the parking brake switch. Is the problem found? | -- | Go to Step 17 | Go to Step 16 |
16 | Check for a short to ground in the wiring between the instrument cluster terminal B9 and the EBCM connector terminal B3. Is the problem found? | -- | Go to Step 17 | go to Step 18 |
17 | Repair the wiring harness as needed. Is the repair complete? | -- | System OK | -- |
18 | Check the brake lamp after doing each of the following functions:
Does the BRAKE warning lamp operate for all of these conditions? | -- | System OK | Go to Step 19 |
19 | When the operations listed in step 18 were performed, the brake warning lamp did not function. Did the BRAKE warning lamp fail to light for all of the operations listed in Step 18? | -- | Go to Step 20 | Go to Step 27 |
20 |
Is the fuse OK? | -- | Go to Step 22 | Go to Step 21 |
21 | Replace the fuse F16. Is the repair complete? | -- | System OK | -- |
22 | Inspect the BRAKE warning lamp bulb. Is the bulb OK? | -- | Go to Step 24 | Go to Step 23 |
23 | Replace the bulb. Is the repair complete? | -- | System OK | -- |
24 |
Does the voltage measure within the value specified? | 11-14 V | Go to Step 25 | Go to Step 26 |
25 |
Is the repair complete? | -- | System OK | -- |
26 |
Is the repair complete? | -- | System OK | -- |
27 | Apply the parking brake again. Does the parking brake warning lamp operate with the parking brake applied? | -- | Go to Step 28 | Go to Step 30 |
28 | Remove the brake fluid reservoir cap. Does the parking brake warning lamp operate with the cap from the brake fluid reservoir removed? | -- | Go to Step 28 | Go to Step 30 |
29 | Check for an open between the instrument cluster connector terminal B8 and the EBCM connector terminal B3. Is the problem found? | -- | Go to Step 17 | Go to Step 13 |
30 |
Is the BRAKE warning lamp on? | -- | Go to Step 10 | Go to Step 31 |
31 |
Is the repair complete? | -- | System OK | Go to Step 32 |
32 |
Is the BRAKE warning lamp on? | -- | Go to Step 8 | Go to Step 33 |
33 |
Is the BRAKE warning lamp on? | -- | Go to Step 34 | Go to Step 35 |
34 | Repair the open in the wiring between ground and the brake fluid level switch. Is the repair complete? | -- | System OK | -- |
35 | Repair the open in the wiring between the instrument cluster connector terminal B8 and the brake fluid level switch. Is the repair complete? | -- | System OK | -- |
