1. Inspection of Control Unit Power Supply Circuit

No. 1 Inspection Of Control Unit Power Supply Circuit

DESCRIPTION OF OPERATION
The power is supplied through the ignition switch (IG1) and cruise control main switch to the control unit.

1. When the cruise control main switch is set to ON with the ignition switch at ON, the current from switch S1 flows through relay Ry1 in the switch. Accordingly, the contact of relay Ry1 is closed and the power is supplied to the control unit.

2. When the main switch is released, it automatically returns to the neutral position. Since the current from switch S2 flows to relay Ry1, the contact of relay Ry1 remains closed.

3. When the main switch is set to OFF, current to relay Ry1 is interrupted. This opens the contact of relay Ry1 to stop the power supply to the control unit. When the switch is released, it automatically returns to the neutral position, but relay Ry1 stays in the OFF state.

4. When the ignition switch is set to OFF while relay Ry1 in the main switch is ON, relay Ry1 is forced to the OFF state just like when the main switch is set to OFF. Even if the ignition switch is set to ON again, relay Ry1 stays in the OFF state until the main switch is set to ON.

NOTE: The numbers beside each connector correspond to those in the "HARNESS AND COMPONENTS LAYOUT".

TROUBLESHOOTING HINTS

ECU Terminal Voltage: