PRE-RELEASE
DTC B3650
| DTC B3650 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| DTC Descriptor |
DTC B3650 08
High Beam Request Signal Circuit Performance - Signal Invalid
| Diagnostic Fault Information |
| Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
| Headlamp High Beam Signal | B3650 08 | 1 | 1 | - |
| Headlamp Flash To Pass Signal | B3806 00 | 2 | 2 | - |
| Turn Signal/Multifunction Switch Ground | - | 1, 2 | - | - |
| 1. Headlamp Dimmer Switch Malfunction 2. Headlamp Flash To Pass Switch Malfunction | ||||
| Circuit/System Description |
The BCM monitors the voltage level within the high beam signal circuit and the flash to pass signal circuit. When the turn signal/multifunction switch is moved to the high beam position or to the flash to pass position, the voltage within the appropriate signal circuit drops to less than 1 V. The BCM will detect the voltage drop and will command the headlamp high beams to turn ON or OFF.
| Conditions for Running the DTC |
Battery voltage must be between 9-16 V.
| Conditions for Setting the DTC |
The BCM detects a short to ground in the headlamp high beam signal circuit.
| Action Taken When the DTC Sets |
The high beam headlamps will malfunction.
| Conditions for Clearing the DTC |
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The DTC will be current for as long as the fault is present.
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When the fault is no longer present, the DTC will be a history DTC.
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A history DTC will clear after 50 ignition cycles.
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| Reference Information |
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Exterior Lighting Systems Description and Operation
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Verification |
Ignition ON, observe the scan tool High Beam Select Switch parameter while pulling and releasing the turn signal/multi-function switch. The value should change between Inactive and Active when changing between the selected states.
| Circuit/System Testing |
| 1. |
Ignition OFF, disconnect at the S78 turn signal/multifunction switch.
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| 2. |
Ignition ON, verify that the scan tool High Beam Select Switch parameter is Inactive.
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| 3. |
If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the K9 BCM.
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| 4. |
Connect a 3 A fused jumper wire between the signal circuit terminal 2 and ground. Verify that the scan tool High Beam Select Switch parameter is Active.
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| 5. |
If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
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| 6. |
If all circuits test normal, test or replace the S78 turn signal/multifunction switch.
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| Component Testing |
Turn Signal/Multifunction Switch Test
| 1. |
Ignition OFF, disconnect the harness connector at the S78 turn signal/multifunction switch.
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| 2. |
Test for Infinite resistance between the terminals listed below with the switch in the open position.
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Signal terminal 2 and ground terminal 3
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Signal terminal 4 and ground terminal 3
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| 3. |
If not the specified value, replace the S78 turn signal/multifunction switch.
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| 4. |
Test for less than 2 Ω between the signal terminal 2 and the ground terminal 3 with the switch in the high beam position.
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| 5. |
If greater than the specified value, replace the S78 turn signal/multifunction switch.
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| 6. |
Test for less than 2 Ω between the signal terminal 4 and the ground terminal 3 while holding the switch in the flash to pass position.
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| 7. |
If greater than the specified value, replace the S78 turn signal/multifunction switch.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Turn Signal Multifunction Switch Replacement
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Control Module References
for BCM replacement, programming and setup
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