GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 Savana 🢒 Brakes 🢒 Hydraulic Brakes 🢒 Brake Warning Alarm Always On

Circuit Description

The Brake Warning indicator illuminates and the power brake booster fluid flow alarm sounds when ground is applied to the brake warning indicator voltage 2 circuit.

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. This step tests for a shorted p/b booster fluid pressure alarm switch.

    2.

  2. This step tests if the p/b booster fluid flow and pressure alarm delay module is applying ground to the brake warning indicator voltage 2 circuit.

Step

Action

Yes

No

Schematic Reference: Brake Warning System Schematics

1

Did you review the Brake Warning System Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Hydraulic Brakes

2

Does the brake assist system operate properly?

Go to Step 3

Go to Brake Assist System Diagnosis

3

Start the engine.

Does the power brake booster fluid flow alarm sound continuously?

Go to Step 4

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

4

  1. Turn OFF the ignition.
  2. Disconnect the power brake booster fluid pressure alarm Switch.
  3. Turn ON the ignition.

Does the power brake booster fluid flow alarm sound continuously?

Go to Step 6

Go to Step 5

5

Replace the power brake booster fluid pressure alarm switch.

Did you complete the replacement?

Go to Step 10

--

6

  1. Turn OFF the ignition.
  2. Disconnect the p/b booster fluid flow and pressure alarm delay module.
  3. Turn ON the ignition.

Does the power brake booster fluid flow alarm sound continuously?

Go to Step 8

Go to Step 7

7

Test the brake fluid level sensor signal circuit for a short to ground. Refer to Circuit Testing in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 9

8

Repair the short to ground in the brake warning indicator supply voltage 2 circuit. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 10

--

9

Replace the p/b booster fluid flow and pressure alarm delay module.

Did you complete the replacement?

Go to Step 10

--

10

  1. Reconnect any previously disconnected components.
  2. Start the engine.

Does the power brake booster fluid flow alarm sound continuously?

Go to Step 2

System OK