B4 Diode Resistor Element, Circuit 531

B4 DIODE RESISTOR ELEMENT/CIRCUIT 531

- Disconnect the fluid level switch.

- Connect a jumper wire from circuit 531 (DG/Y) to known chassis ground.

- Observe the red brake light.

Does the brake light function?

> Yes
Leave the fluid level switch disconnected. Go to pinpoint Test B5. [1][2]B5 - Master Cylinder Fluid Level Switch

> No
Repair the open in circuits 977 (P/W), 531 (DG/Y) or the open diode/resistor element. Repeat the System Precheck.