Park Avenue V6-231 3.8L VIN L SFI (1993)
Impact Sensor: Description and Operation
Arming Sensor
The arming sensor is contained in the same housing as the passenger compartment discriminating sensor. This assembly is referred to as the dual
sensor. Although both sensors require replacement as an assembly, they are referred to independently.
The arming sensor is a switch located in the deployment loop's power feed side (high side). The arming sensor Is calibrated to close at low level
velocity changes (lower than the discriminating sensors). This assures that the inflator module is connected directly to the DERM's 36 VLR or
"Ignition 1" voltage when either discriminating sensor closes.
The arming sensor consists of a sensing element, normally open switch contacts, a diagnostic resistor and two steering diodes. The sensing element
closes the normally open switch contacts when the vehicle velocity changes at a rate indicating potential need for deployment.
The diagnostic resistor is connected in parallel with the normally open switch contacts and allows a small amount of current through the
deployment loop during normal non-deployment conditions. This small current flow results in voltage drops across each component within the
loop. The DERM monitors these voltage drops to detect circuit or component faults. The two steering diodes provide isolation between the 36
VLR output of the DERM and "Ignition 1" voltage.
