Sprinter 2500 V6-3.0L DSL Turbo VIN 45 (2007)
Clockspring Assembly / Spiral Cable: Description and Operation
Operation
OPERATION
The clockspring is a mechanical electrical circuit component that is used to provide continuous electrical continuity between the fixed vehicle wire
harness and certain electrical components mounted on or in the rotating steering wheel. On this vehicle the rotating electrical components include the
driver airbag, the horn switch and, on vehicles so equipped, the steering wheel switches. The clockspring is positioned and secured near the top of the
steering column. The fixed connector receptacles on the underside of the clockspring case connect the clockspring to the vehicle electrical system
through a take out and connector from the vehicle wire harness and through self-docking direct interface connectors to the multi-function switch and, on
vehicles so equipped, to the speed control switch.
The turn signal cancel cam integral to the clockspring rotor is movable and is keyed so as to move with the rotation of the steering column shaft and the
steering wheel. The integral lobes of the cancel cam formation on the lower surface of the clockspring rotor hub contact the turn signal cancel actuator of
the multi-function switch to provide automatic turn signal cancellation. The yellow sleeved pigtail wire on the upper surface of the clockspring rotor
connects the clockspring to the driver airbag, while two single pigtail wires connect to the feed and ground terminals of the horn switch located within
the hub cavity of the steering wheel. Additional pigtail wires connect to the optional steering wheel switches on vehicles so equipped.
Like the clockspring in a timepiece, the clockspring tape has travel limits and can be damaged by being wound too tightly during full stop-to-stop
steering wheel rotation. To prevent this from occurring, the clockspring is centered when it is installed on the steering column. Centering the clockspring
indexes the clockspring tape to the movable steering components so that the tape can operate within its designed travel limits. However, if the
clockspring is removed from the steering column or if the steering shaft is disconnected from the steering gear, the clockspring spool can change position
relative to the other steering components. The clockspring must be re-centered following completion of this service or the tape may be damaged.
Service replacement clocksprings are shipped pre-centered and with a plastic locking pin installed. This locking pin should not be removed until the
clockspring has been installed on the steering column. If the locking pin is removed before the clockspring is installed on a steering column, the
clockspring centering procedure must be performed.
The hard wired clockspring circuits as well as the hard wired inputs and outputs of the SCM and the SAS may be diagnosed using conventional
diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the
diagnosis of the SCM, the SAS or the electronic controls or communication between other modules and devices that provide features affected by these
components. The most reliable, efficient, and accurate means to diagnose the SCM, the SAS, the Controller Area Network (CAN) data bus or the
electronic communication related to SCM and SAS operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.
