deploy the airbags for up to one second following a
battery disconnect or failure during an impact. The
purpose of the capacitor is to provide backup airbag
system protection in case there is a loss of battery
power supply to the ACM.
CLOCKSPRING
DESCRIPTION
The clockspring assembly is mounted with two
screws to the multi-function switch mounting hous-
ing near the top of the steering column behind the
steering wheel. The clockspring is used to maintain a
continuous electrical circuit between the fixed instru-
ment panel wire harness connector on the steering
column and several electrical components that rotate
with the steering wheel. The rotating components
include the driver side airbag module, the horn
switch, the vehicle speed control switches and, if the
vehicle is so equipped, the remote radio switches.
The clockspring cannot be repaired. If the clock-
spring is faulty, damaged, or if the driver side airbag
has been deployed, the clockspring must be replaced.
OPERATION
The clockspring assembly consists of a plastic case
which contains a flat, ribbon-like, electrically conduc-
tive tape that winds and unwinds like a clockspring
with the steering wheel rotation. The electrically con-
ductive tape consists of several fine gauge copper
wire leads sandwiched between two narrow strips of
plastic film.
Like the clockspring in a timepiece, the clockspring
tape has travel limits and can be damaged by being
wound too tightly. 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 other steering components so
that it can operate within its designed travel limits.
However, if the clockspring is removed for service or
if the steering column is disconnected from the steer-
ing gear allowing the clockspring tape to change posi-
tion relative to the other steering components, it
must be re-centered following completion of the ser-
vice or it may be damaged. Refer to Clockspring
Centering in the Adjustments section of this group
for the proper centering procedures.
Service replacement clocksprings are shipped pre-
centered and with a locking pin installed. This lock-
ing 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 locking pin cannot
be reinstalled and the clockspring centering proce-
dure must be performed.
DIAGNOSIS AND TESTING
AIRBAG SYSTEM
A DRBIII
t scan tool is required for diagnosis of the
airbag system. See the proper Diagnostic Procedures
manual for more information.
(1) Connect the DRBIII
t scan tool to the 16-way
data link wire harness connector. The connector is
located on the driver side lower edge of the instru-
ment panel, outboard of the steering column (Fig. 1).
(2) Turn the ignition switch to the On position.
Exit the vehicle with the DRBIII
t. Be certain that
the DRBIII
t contains the latest version of the proper
DRB software.
(3) Using the DRBIII
t, read and record the active
Diagnostic Trouble Code (DTC) data.
(4) Read and record any stored DTC data.
(5) See the proper Diagnostic Procedures manual if
any DTC is found in Step 3 or Step 4.
(6) After completing the necessary repairs, try to
erase the stored DTC data. If any problems remain,
the stored DTC data will not erase. See the proper
Diagnostic Procedures manual for the procedures to
diagnose any active/stored DTC that will not erase.
(7) With the ignition switch still in the On posi-
tion, check to be certain that nobody is in the vehicle.
(8) From outside of the vehicle (away from the air-
bags in case of an accidental deployment) turn the
ignition switch to the Off position for about ten sec-
Fig. 1 16-Way Data Link Connector - Typical
1 – 16–WAY DATA LINK CONNECTOR
2 – BOTTOM OF INSTRUMENT PANEL
8M - 4
PASSIVE RESTRAINT SYSTEMS
WJ
DESCRIPTION AND OPERATION (Continued)