Seat Belt Indicator Malfunction - Rear
Diagnostic Instructions
Diagnostic Fault Information
Circuit
|
Short to Ground
|
High Resistance
|
Open
|
Short to Voltage
|
Signal Performance
|
Rear Seat Belt Switch Signal
|
1
|
2
|
2
|
2
|
-
|
Rear Seat Belt Switch Low Reference
|
-
|
2
|
2
|
2
|
-
|
1. Green indicator will illuminate only for the bulb check. The
red indicator will remain ON with seat belt buckled.
2. Green indicator will illuminate only for the bulb check. The
red indicator will never illuminate.
|
|
|
Circuit/System Description
All three rear seat belt switches are 2-wire switch wired to the
inflatable restraint sensing and diagnostic module (SDM) using a
signal circuit and a low reference circuit. When the seat belt is
unbuckled the switch is closed, and when the seat belt is buckled
the switch is open. The SDM sends the status of the rear seat belt
via serial data to the driver information center. After receiving
the message, the driver information center controls the
illumination of the driver seat belt indicator.
Reference Information
Schematic Reference
Seat Belt Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Seat Belt System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Diagnostic Aids
1. |
The mechanical stop in the
buckle may prevent latching but the switch in the buckle may
momentarily open and the SDM would interpret this as an occupant in
the rear seat position and that the buckle was attempting to
latch. |
2. |
If a rear occupant attempts to
latch the seat belt into the wrong buckle, the indicatormay
illuminate and the system assumes there is an occupant not buckled
in that seat position. |
3. |
An unseated connector can
appear as a buckled seat belt connection. |
Circuit/System Verification
1. |
Verify that all connectors are
fully seated. |
2. |
With the scan tool monitor the
2nd Row Seat Belt Status parameter while buckling and unbuckling
the seat belt. The parameter should display Buckled and Unbuckled
when buckling and unbuckling the seat belt. |
⇒ If the parameter
does not display Buckled and Unbuckled when buckling and unbuckling
the seat belt
⇒ |
Replace the P9 driver information center. |
⇓ If the parameter
does display Buckled and Unbuckled when buckling and unbuckling the
seat belt
Refer to Circuit/System Testing.
Circuit/System Testing
Note: When removing
connectors inspect for damage or corrosion. Damage or corrosion in
the following requires repair or replacement of the affected
component/connector.
• |
Seat belt switch
harness connector |
• |
SDM wiring harness
connector |
2. |
Disconnect the harness
connector at the B88 seat belt switch. |
3. |
Test for less than 5 Ω
between the ground circuit terminal 2 and ground. |
⇒ If 5 Ω or
greater
|
3.1 |
Disconnect the harness
connector at the K36 SDM. |
|
3.2 |
Test for less than 2 Ω
in each control circuit end to end. |
⇒ |
If 2 Ω or greater, repair the open/high resistance in the
circuit. |
⇒ |
If less than 2 Ω, replace the K36 SDM. |
5. |
Verify the scan tool 2nd Row
Seat Belt Status parameter displays Buckled. |
⇒ If the scan tool
2nd Row Seat Belt Status parameter does not display
Buckled
|
5.1 |
Disconnect the harness
connector at the K36 SDM. |
|
5.2 |
Test for infinite resistance
between the seat belt switch signal circuit terminal 1 and
ground. |
⇒ |
If less than infinite resistance, repair the short to ground on
the circuit. |
⇒ |
If less than 2 Ω, replace the K36 SDM. |
⇓ If the scan tool
2nd Row Seat Belt Status parameter does display
Buckled
6. |
Install a 3 A fused jumper
wire between the circuit terminal 1 and the ground circuit terminal
2. |
7. |
Verify the scan tool 2nd Row
Seat Belt Status parameter displays Unbuckled. |
⇒ If the scan tool
2nd Row Seat Belt Status parameter does not display
Unbuckled
|
7.1 |
Disconnect the harness
connector at the K36 SDM. |
|
7.3 |
Test for less than 1 V between
the signal circuit and ground. |
⇒ |
If 1 V or greater, repair the short to voltage on the
circuit. |
|
7.4 |
Test for less than 2 Ω
in each circuit end to end. |
⇒ |
If 2 Ω or greater, repair the open/high resistance in the
circuit. |
⇒ |
If less than 2 Ω, replace the K36 SDM. |
⇓ If the scan tool
2nd Row Seat Belt Status parameter does display
Unbuckled
8. |
Replace the B88 seat belt
switch. |
Component Testing
2. |
Disconnect the harness
connector at the B88 seat belt switch. |
3. |
B88 seat belt switch in the
open position. |
4. |
Test for infinite resistance
between the signal circuit terminal 1 and the ground terminal 2 at
the B88 seat belt switch. |
⇒ If there is not
infinite resistance
⇒ |
Replace the B88 seat belt switch. |
⇓ If there is
infinite resistance
5. |
B88 seat belt switch in the
closed position. |
6. |
Test for less than 1 Ω
between the signal circuit terminal 1 and the ground terminal 2 at
the B88 seat belt switch. |
⇒ If 1 Ω or
greater
⇒ |
Replace the B88 seat belt switch. |
⇓ If less than 1
Ω
Repair Instructions
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