Jeep WK2 Grand Cherokee Active Head Restraints

By Jeep Experts

WARNING:

All occupants, together with the driving force, mustn’t function a car or sit in a car’s seat till the pinnacle restraints are positioned of their correct positions so as to reduce the danger of neck harm within the occasion of a collision. Do not place objects excessive of the Active Head Restraint, comparable to coats, seat covers or transportable DVD gamers. These objects could intrude with the operation of the Active Head Restraint within the occasion of a collision and will end in critical harm or demise.

Active Head Restraints could also be deployed if they’re struck by an object comparable to a hand, foot or free cargo. To keep away from unintended deployment of the Active Head Restraint, be sure that all cargo is secured, as free cargo might contact the Active Head Restraint throughout sudden stops. Failure to observe this warning might trigger private harm if the Active Head Restraint is deployed.

AHR COMPONENTS

Active head restraints are these which require the car occupants to take some motion to provoke, comparable to digital stability management. A passive system doesn’t require any motion by the car occupants to function. It merely prompts when a set of standards or sequence of occasions happen.

While the brand new Active Head Restraints (AHR) are passive in operation, they’re known as an lively system. The AHR system is designed to deploy within the occasion of a rear collision with the gear selector in any gear besides Reverse. The AHR system is normal tools for each entrance seats on the 2011-up Grand Cherokees.

The AHR system has a linkage allowing the decrease a part of the pad to tilt ahead for consolation. It additionally features a linkage that articulates the pad throughout deployment, a caliper-type latch mechanism, and the latch striker.

The solely electrical element of the AHR unit is a latch-release solenoid and the pigtail wire that connects the solenoid to the car’s electrical system. The ORC doesn’t monitor the latch for an open or closed place. The pigtail wire and connector are routed by way of the middle of the proper assist posts and down by way of the information sleeve into the inside of the seat again. The pigtail wire and connector are linked to a devoted takeout and connector of the seat wire harness.

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AHR CONSTRUCTION

An AHR is quickly distinguished from a non-active head restraint by the two-piece development used for an AHR. The entrance half meeting consists of a molded strengthened plastic kind lined with a foam pad and is trimmed in a cloth coordinated with the opposite gentle trim on the seat. The rear half floor is supplied with a tough moulded plastic trim cowl that matches the opposite arduous trim on the seat. Located between the pad and the trim cowl is the assist construction of the AHR and each the mechanical and electrical elements of the unit.

The assist posts for the AHR models function quite a few notches that have interaction spring-loaded pins into detents situated on the assist put up. The spring mechanism is integral to the plastic information sleeves. These sleeves are used for manually adjusting the vertical top of the meeting to correctly match the seat occupant.

The entrance half of the pinnacle restraint extends ahead to make the most of the hole between the again of the occupant’s head and the pinnacle restraint. The system is designed to assist stop or scale back the extent of accidents to the driving force and entrance passenger in sure forms of rear impacts.

OCCUPANT RESTRAINT CONTROLLER

The ORC displays the situation of the AHR unit circuits. It illuminates the air bag indicator within the Cabin Compartment Node (CCN) and shops a DTC for any detected fault. There is not any air bag gentle illumination if solely the AHR is deployed.

Unlike different elements of the restraint system, the ORC provides energy to the actuators to activate the AHR system. The ORC displays inputs from the entrance influence sensors and its inner accelerometer. It additionally displays email correspondence inputs obtained over the Controller Area Network (CAN) knowledge bus to find out when the circumstances exist to deploy each AHR models.

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When the ORC sends the correct electrical deployment sign to the solenoid of the AHR unit, the solenoid releases the AHR latch. When the AHR latch is launched, the stress of the spring-loaded linkage throughout the AHR mechanically drives the AHR pad ahead. If at any level the AHR is available in contact with the occupant’s head, it stops the ahead motion and locks to carry the pinnacle.

AHR DEPLOYMENT / RESETTING / SERVICE

If the Active Head Restraints are triggered throughout a collision, the entrance half of the pinnacle restraint might be prolonged ahead and separated from the rear half of the pinnacle restraint. Do not drive your car after the AHRs have deployed. The head restraint have to be reset into the unique place to greatest shield the occupant for every type of collisions. An licensed FCA US LLC seller should reset the AHRs on the driving force’s and entrance passenger’s seat earlier than driving. Personally trying to reset the AHRs could end in injury to the AHRs that might impair their operate.

AHR OPERATION

The Active Head Restraint (AHR) models are deployed by a sign generated by the Occupant Restraint Controller (ORC) by way of the primary row proper and left solenoid and floor sign circuits. The ORC logic displays inputs from the entrance influence sensors in addition to email correspondence inputs obtained over the Controller Area Network (CAN) knowledge bus to find out when the suitable circumstances exist to ship a deployment sign to each AHR models. When the ORC detects an influence pulse of enough magnitude originating from the rear of the car, whereas any transmission gear is chosen besides Reverse (R), the ORC sends the deployment indicators.

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When the ORC sends the correct electrical deployment sign to the solenoid of the AHR unit, the solenoid releases the AHR latch. When the AHR latch is launched, the stress of the spring-loaded linkage throughout the AHR mechanically drives the AHR pad by way of a brief, barely ahead and upward arc to the ultimate deployed place. Deployment of the AHR reduces the area between the again of the pinnacle of the seat occupant and the pinnacle restraint pad. Closing this area helps the pinnacle of the seat occupant throughout a low velocity rear influence collision occasion and is necessary in decreasing or eliminating doubtlessly debilitating cervical (also referred to as whiplash) accidents.

The ORC displays the situation of the AHR unit circuits, and can illuminate the airbag indicator within the ElectroMechanical Instrument Cluster (EMIC) (also referred to as the Cab Compartment Node/CCN) and retailer a Diagnostic Trouble Code (DTC) for any fault that’s detected.

The arduous wired circuits between the AHR models and the ORC could also be recognized utilizing standard diagnostic instruments and procedures. Refer to the suitable wiring info. However, standard diagnostic strategies won’t show conclusive within the analysis of the AHR models or the digital controls or communication between different modules and units that present some options of the Supplemental Restraint System (SRS). The most dependable, environment friendly, and correct means to diagnose the AHR models or the digital controls and communication associated to AHR unit operation requires using a diagnostic scan software. Refer to the suitable diagnostic info.

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