RAM 1500 Truck 4WD V8-5.9L VIN Z (2002)
Fig. 51 Side Curtain Airbag
Vehicles equipped with side curtain airbags have two individually controlled curtain airbag units. These airbag units are concealed and mounted
above the headliner where they are each secured to one of the roof side rails. Each folded airbag cushion is contained within a long extruded
plastic channel that extends along the roof rail from the A-pillar at the front of the vehicle to just behind the B-pillar on standard cab models, and
to just behind the C-pillar on quad cab models. A tether extends down the A-pillar from the front of the airbag cushion, where it is retained to the
pillar with plastic push-in routing clips and it is secured to the base of the A-pillar near the belt line with a screw.
The hybrid-type inflator for each airbag is secured to the roof rail at the rear of the airbag unit behind the B-pillar (standard cab) or C-pillar (quad
cab), and is connected to the airbag cushion by a long tubular manifold. The inflator bracket and the airbag cushion channel are located with
plastic push-in fasteners to the roof rail, then secured with screws to spring nuts located in the roof rail. A two-wire take out of the body wire
harness with a keyed and latched connector insulator connects directly to an integral receptacle on the inflator initiator.
The side curtain airbag unit cannot be adjusted or repaired and must be replaced if deployed, faulty, or in any way damaged. Once a side curtain
airbag has been deployed, the complete airbag unit, the headliner, the upper A, B, and C-pillar trim, and all other visibly damaged components
must be replaced.
Each side curtain airbag is deployed individually by an electrical signal generated by the left or right Side Impact Airbag Control Module (SIACM
) to which it is connected through left or right curtain airbag line 1 and line 2 (or squib) circuits. The hybrid-type inflator assembly for each airbag
contains a small canister of highly compressed inert gas. When the SIACM sends the proper electrical signal to the airbag inflator, the electrical
energy creates enough heat to ignite chemical pellets within the inflator. Once ignited, these chemicals burn rapidly and produce the pressure
necessary to rupture a containment disk in the inert gas canister. The inflator and inert gas canister are sealed and connected to a tubular manifold
so that all of the released gas is directed into the folded curtain airbag cushion, causing the cushion to inflate.
As the airbag cushion inflates it will drop down from the roof rail between the edge of the headliner and the side glass/body pillars to form a
curtain-like cushion to protect the vehicle occupants during a side impact collision. The front tether keeps the front portion of the bag taut, thus
ensuring that the bag will deploy in the proper position. Following the airbag deployment, the airbag cushion quickly deflates by venting the inert
gas through the loose weave of the cushion fabric, and the deflated cushion hangs down loosely from the roof rail.
