Bosch Tester (Digital Display Deviates)
- Turn off ignition. Check wires between terminals No. 29 and 32 of disconnected control unit plug for opens and for continuity of diode. Check wire between control unit plug terminal No. 29 and instrument cluster terminal No. 2 for open.
- Check plug connection of indicator light, ground wire and solenoid valve relay plug connection for voltage drop. Repair or replace wiring as necessary. Replace hydraulic unit if diode is defective and wiring is okay.