Grand Cherokee 2WD V8-4.7L VIN J (2004)
Hood Sensor/Switch (For Alarm): Description and Operation
Fig.1 Hood Ajar Switch
HOOD AJAR SWITCH
The hood ajar switch is a self-adjusting, normally closed, single pole, double throw momentary switch that is used only on vehicles built for sale in
certain international markets where it is required equipment. The mounting bracket is fastened to the left inner fender. A molded plastic striker
with three integral retainers is secured to the underside of the hood panel inner reinforcement to actuate the switch plunger as the hood panel is
closed.The switch receives a path to ground through the left inner fender shield in the engine compartment.
The hood ajar switch adjusts itself as the striker pushes the switch body down through the switch when the hood panel is closed after the initial
installation. This self-adjustment feature is only functional the first time the hood is closed following installation. If the switch requires adjustment
following the initial installation, the switch must be replaced.
The normally closed hood ajar switch is normally held open when the hood panel is closed and latched. When the hood is opened, the switch
plunger extends from the switch body and the switch contacts are closed. The hood ajar switch is connected in series between ground and the hood
ajar switch sense input of the Body Control Module (BCM). The BCM uses an internal resistor pull up to monitor the state of the hood ajar switch
contacts. The hood ajar switch can be diagnosed using conventional diagnostic tools and methods.
