Switch For Start Control Unit (SCU), Description

The start control unit (SCU) is mounted in the dashboard next to the steering wheel. Besides the cylinder to receive the key, the start control unit (SCU) also contains an antenna cable and four switches. There is one switch for each of the three key positions (I-III) and one to indicate that the key has been inserted into the ignition.

If the keyless vehicle module (KVM) is installed, the key need not be inserted in the ignition where a starter knob is fitted instead. The starter knob must be pressed in before it can be turned from 0 to I and activate the key-in switch. The key identity is checked via the antennae in the passenger compartment that are connected to the keyless vehicle module (KVM).

The ignition's four switches: 

• Key-in switch. Also called S-supply switch.
• Ignition X-supply switch.
• Ignition 15-supply switch.
• Ignition 50-supply switch.

Valid key positions 

• Key out.
• Key position 0.
• Key position I.
• Key position II.
• Key position II/III. Occurs when key turned from position II to III.
• Key position III.