Description And Operation: CLOCKSPRING

DESCRIPTION 

Courtesy of CHRYSLER GROUP, LLC

The clockspring for this vehicle is secured to the stalk unit near the top of the steering column below the steering wheel. The clockspring also includes an integral, internal turn signal cancel cam and is serviced as a unit with the stalk unit. The stalk unit also supports the left (lighting) multifunction switch stalk, the right (wiper) multifunction switch stalk and, on vehicles so equipped, a third cruise control switch stalk located below the lighting switch stalk on the left side of the stalk unit. Each of these switches and the wiring between the switches and the clockspring can not be separated and are serviced as a complete assembly with the stalk unit. The clockspring case includes integral tabs for mounting the unit to the stalk unit. The clockspring, the stalk unit and each of the switch stalks are constructed of molded plastic.

The stalk unit case includes two connector receptacles. One on the bottom of the unit facing downward contains the circuits for the clockspring. Within the plastic case is a spool-like molded plastic rotor with a large exposed hub. The upper surface of the rotor hub has a large center hole, up to two short airbag squib pigtail wires with connectors, a pigtail wire for the horn switch and, if the vehicle is so equipped, additional pigtail wires for the steering wheel switches. Wound around the rotor spool within the case is a long ribbon-like tape that consists of several thin copper wire leads sandwiched between two thin plastic membranes. The outer end of the tape terminates at the connector receptacle on the bottom of the unit, while the inner end of the tape terminates at the pigtail wires on the hub of the clockspring rotor that face the steering wheel. The outer surface of the rotor hub rim within the clockspring case also has the integral lobes of the turn signal cancel cam.

The service replacement clockspring is shipped pre-centered and has a molded plastic locking pin installed. The locking pin secures the centered clockspring rotor to the clockspring case during shipment and handling, and must be removed after the clockspring is mounted to the steering column, but before the steering wheel is installed. It is recommended that adhesive tape or an additional strap be installed through the two retainer loops integral to the outer circumference of the clockspring rotor and the stalk unit case to secure the rotor to the case while the clockspring is removed from the steering column to prevent accidental loss of clockspring centering.

The clockspring cannot be repaired. If the clockspring is ineffective, damaged, or if the Driver AirBag (DAB) has been deployed, the entire clockspring, turn signal cancel cam, the stalk unit and multifunction switches must be replaced.

OPERATION 

The clockspring is a mechanical electrical circuit component that is used to provide continuous electrical continuity between the fixed instrument panel 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 (DAB), the horn switch, the remote radio switches and the hands free communication switches, if the vehicle is so equipped. The clockspring is positioned and secured near the top of the steering column. The fixed connector receptacle on the bottom of the fixed clockspring case connects the clockspring to the vehicle electrical system through a take out and connector from the instrument panel wire harness.

The turn signal cancel cam is integral to the rim of the clockspring rotor hub within the clockspring case so it also moves with the rotation of the steering wheel. Short pigtail wires on the upper surface of the clockspring rotor connect the clockspring to the DAB, to the horn switch and, if the vehicle is so equipped, to the optional remote radio and hands free communication switches on the steering wheel.

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. If the steering wheel is removed from the steering column or if the clockspring is removed from the steering column, a spring-actuated automatic locking ring pops up from the face of the clockspring rotor to lock the rotor from rotation. However, if the locking ring is manually compressed or if the steering shaft is disconnected from the steering gear with the steering wheel installed, the clockspring spool can change position relative to the other steering components. Loss of clockspring centering will result in damage to the clockspring tape.

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, clockspring centering may be compromised.

The hardwired clockspring circuits 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 clockspring squib circuits for the Supplemental Restraint System (SRS). The most reliable, efficient and accurate means to diagnose the circuits related to SRS operation requires the use of a diagnostic scan tool and may also require the use of the Airbag Kit. Refer to the appropriate diagnostic information.