Airbag system – general information
These models are equipped with a Supplemental Restraint System (SRS), more commonly called an airbag system. There are at least two airbags, one for the driver and one for the front seat passenger, on all models. The SRS system is designed to protect the driver and passenger from serious injury in the event of a head-on or frontal collision. The airbag control module is located on the transmission tunnel, below the center of the instrument panel. Some models are also equipped with optional side curtain airbags. Vehicles with this option can be identified by the «SRS -AIRBAG» logo printed on the headliner above the B-pillar.
Airbag modules
The airbag module houses the airbag and the inflator unit. The inflator unit is mounted on the back of the housing over a hole through which gas is expelled, inflating the bag almost instantaneously when an electrical signal is received from the airbag control module. On the driver’s airbag, the specially wound wire that carries this signal to the module is called a clockspring. The clockspring is a flat, ribbon-like electrically conductive tape that winds and unwinds as the steering wheel is turned so it can transmit an electrical signal regardless of wheel position. The procedure for removing the driver’s airbag is part of Steering wheel – removal and installation in Suspension and steering systems.
The passenger airbag is located in the top of the dashboard, above the glove box. There’s also a passenger airbag ON/OFF switch located at the lower right corner of the center instrument panel bezel. This switch allows you to deactivate the passenger airbag if you’re transporting an infant or a young child in a child safety seat. We don’t recommend removing the passenger airbag because there is no reason to do so unless it has been activated during an accident and needs to be replaced afterward. Although the electrical connector for the passenger airbag must be disconnected when removing the instrument panel (see Body), the airbag module itself does not need to be removed.
Optional side-curtain airbags, if equipped, are located on each roof side rail, above the headliner, and they extend from the A-pillar to the C-pillar on quad cab models. Again, we don’t recommend trying to remove the side-curtain airbags because there is no reason to do so unless they’ve been deployed in an accident and must be replaced.
Airbag Control Module (ACM) and Side Impact Airbag
Control Modules (SIACMs)
The Airbag Control Module (ACM) is the microprocessor that monitors and operates the airbag system. The ACM checks the system every time the vehicle is started. When you start the car, an AIRBAG indicator light comes on for about six seconds, then goes off, if the system is operating properly. If there is a fault in the system, the ACM stores a Diagnostic Trouble Code (DTC) and illuminates the AIRBAG indicator light, which remains on until the problem is repaired and the ACM memory is cleared of any DTCs. If the AIRBAG indicator light comes on at any time other than the bulb test and remains on, or doesn’t come on at all, there’s a problem in the system. A DRBIII scan tool is the only means by which the system can be diagnosed. Take the vehicle to your dealer immediately and have the system professionally diagnosed and repaired.
The ACM controls the operation of the standard driver and passenger airbags. Vehicles with optional side-curtain airbags are also equipped with Side Impact Airbag Control Modules (SIACMs). There are two SIACMs, one for each side-curtain airbag. The SIACMs are located behind the B-pillar trim, above the outboard front seat belt retractor inside each B-pillar.
Servicing components near the SRS system
There are times when you need to remove the steering wheel, the instrument cluster, the radio, the heater/air conditioning control assembly or other components on or near the dashboard. At these times you’ll be working around components and wire harnesses for the SRS system. Do not use electrical test equipment on airbag system wires; it could cause the airbag (s) to deploy. ALWAYS DISABLE THE SRS SYSTEM BEFORE WORKING NEAR THE SRS SYSTEM COMPONENTS OR RELATED WIRING.
Disabling the system
Whenever working in the vicinity of the steering wheel, steering column, floor console or near other components of the airbag system, the system should be disarmed. To do this, perform the following steps:
a) Turn the ignition switch to the OFF position.
b) Disconnect the cable (s) from the negative battery terminal(s) (see Engine electrical systems).
c) WAIT FOR AT LEAST TWO MINUTES before beginning work (during this two-minute interval the capacitor that provides emergency back-up power to the system loses its charge).
Enabling the system
To enable the airbag system, perform the following steps:
a) Turn the ignition switch to the OFF position.
b) Connect the cable (s) to the negative battery terminal(s).
c) Without putting your body in front of either airbag, turn the ignition switch to the ON position. Note whether the airbag indicator light glows for six seconds, then goes out. If it does, this indicates that the system is functioning properly.