B3

B3 CHECK ELECTRONIC HYDRAULIC CONTROL UNIT (EHCU) FUNCTION

- Key "OFF."

- Install the EEC IV 60-Pin Breakout Box.

- Disconnect the red brake warning indicator relay.

- Disconnect fuse 21 (15A).

- Key "ON."

- Measure the voltage between the red brake warning indicator relay connector pin 4, circuit 977 (P/W) and chassis ground.

Is the voltage 10 volts or greater?

> Yes
Repair short to power in circuit 977 (P/W). B17

> No
B4