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DTC B3950 or B3951

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B3950 01: Left Rear Indicator Circuit Short to Battery

DTC B3950 02: Left Rear Indicator Circuit Short to Ground

DTC B3950 04: Left Rear Indicator Circuit Open

DTC B3951 01: Right Rear Indicator Circuit Short to Battery

DTC B3951 02: Right Rear Indicator Circuit Short to Ground

DTC B3951 04: Right Rear Indicator Circuit Open

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Left Rear Indicator

B3950 02

B3950 04

B3950 01

-

Right Rear Indicator

B3951 02

B3951 04

B3951 01

--

Circuit/System Description

Ground is applied at all times to the indicator/multifunction switch. When the indicator/multifunction switch is placed in either the turn right or turn left position, ground is applied to the right turn or left indicator switch signal circuit to the body control module (BCM) and the trailing lighting converter. The BCM and the trailing lighting converter then applies a voltage to the rear indicator lamps through there respective voltage supply circuits.

Conditions for Running the DTC

B3950 01 and B3951 01

The appropriate indicator is inactive.

B3950 02, B3950 04, B3951 02 or B3951 04

The appropriate indicator is active.

Conditions for Setting the DTC

B3950 01 or B3951 01

The control module detects a short to voltage on the control circuit.

B3950 02 or B3951 02

The control module detects a short to ground on the control circuit.

B3950 04 or B3951 04

The control module detects an open control circuit.

Action Taken When the DTC Sets

The appropriate indicator is inoperative.

Conditions for Clearing the DTC

The condition for setting the DTC is not longer present.

Reference Information

Schematic Reference

Exterior Lamps Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Exterior Lighting Systems Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, command the appropriate Rear Indicator Lamp test. The appropriate rear indicator lamp should be ON/OFF.

Circuit/System Testing
  1. Ignition OFF, disconnect the appropriate harness connector at the tail lamp listed below:
    2. • E4LR Indicator Lamp - Left Rear
    • E4RR Indicator Lamp - Right Rear
  2. Test for less than 5 Ω between the appropriate indicator lamp ground circuit harness connector listed below and ground.
    3. • E4LR Turn Signal Lamp - Left Rear harness connector terminal 3
    • E4RR Turn Signal Lamp - Right Rear harness connector terminal 3
    ⇒If greater than the specified value, test the ground circuit for an open/high resistance.
  3. Connect a test lamp between the appropriate indicator lamp control circuit harness connector listed below and ground.
    4. • E4LR Turn Signal Lamp - Left Rear harness connector terminal 2
    • E4RR Turn Signal Lamp - Right Rear harness connector terminal 2
  4. Command the appropriate Indicator Lamp test ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
    5. ⇒If the test lamp is always ON, test the Signal circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module.
    ⇒If the test lamp is always OFF, test the Signal circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K9 Body Control Module.
  5. If all the circuits test normal, replace the appropriate indicator lamp.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Tail Lamp Replacement
    • Control Module References for BCM or trailer lighting converter replacement, setup and programming
   


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