Code
B1406
ALFA ROMEO
B — Body
Front left electric window lowering switch short to ground
Views:
UK: 1
EN: 6
RU: 7
AI status
Completed
Completed
100%
Causes
- Damaged wiring with insulation breach contacting chassis ground
- Defective front left window switch (internal short)
- Corroded or bent connector terminals causing low-resistance path to ground
- Faulty body control / window control module or grounding point
- Water ingress in door causing short circuits
Symptoms
- Front left window will not lower (or lower only intermittently)
- Window control may be inoperative in the door switch but work from master switch (or vice versa)
- Blown fuse or repeated fuse failures on the window circuit
- Diagnostic trouble code B1406 present; possible abnormal behavior of other door electronics
- Occasional clicking or lack of motor response when switching to lower
What to check
- Verify stored freeze frame / live data for switch/wiring status with a scan tool
- Inspect fuses and relays for the power window circuit
- Visual inspection of door wiring harness through the door hinge boot for chafing
- Check connector at the front left window switch for corrosion, moisture, or bent pins
- Measure voltage at the switch connector with ignition ON (observe safety procedures)
Signal parameters
- Battery voltage at switch power terminal: ~12–14 V with ignition/accessory ON
- Switch output when not pressed: open/near battery voltage (depending on circuit design) — no direct 0 V to chassis ground
- Short-to-ground condition: near 0 V or full continuity to chassis ground on the switch signal line
- Motor current draw when operating: typically several amps (varies by motor); excessive current suggests mechanical bind or short
- Resistance: continuity between the signal/return wire and chassis ground indicates short (low ohms)
Diagnostic algorithm
- Read and record freeze-frame and live data with a diagnostic scanner. Confirm B1406 and any related codes.
- Turn ignition OFF, remove the key, and disconnect battery negative if you will be unplugging connectors or accessing terminals.
- Visually inspect the door harness where it enters the body (rubber boot). Look for broken wires, pinching, or exposed conductors.
- Unplug the front left window switch connector. With ignition ON, measure voltage between the switch power terminal and ground to confirm supply voltage.
- With connector unplugged, check continuity between the suspected switch signal/ground wire and chassis ground. Low resistance indicates a short to ground.
- If short present at connector, isolate by back-probing or disconnecting sections of wiring (door vs body harness) to locate the short area (door harness, boot, or body side).
- Inspect and if necessary remove the switch from the door. Bench-test the switch for internal shorts using a multimeter across terminals while operating the switch.
- Repair damaged wiring (replace or solder and insulate, replace grommet/boot), clean/repair corroded connectors, or replace the switch assembly as indicated.
- After repair, clear codes and retest operation multiple cycles. Monitor for code return and verify proper window function.
- If wiring and switch check OK but code persists, test/inspect the body control/window module grounds and outputs; consider module fault and consult service manual for advanced testing.
Likely causes
- Frayed or pinched harness where the door wiring passes through the hinge/boot
- Short inside the switch assembly (common after spill or wear)
- Connector plug at the switch has corrosion, bent pins or back-pin to ground
- Aftermarket accessory or previous repair damaged the wiring
- Poor/loose ground at door or body ground strap
Fault status
Status
Front left power window lowering switch circuit: short to ground detected.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
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Code
B1406
FIAT
B — Body
Front left electric window lowering switch short to ground
Views:
UK: 2
EN: 6
RU: 7
AI status
Completed
Completed
100%
Causes
- Damaged wiring with insulation breach contacting chassis ground
- Defective front left window switch (internal short)
- Corroded or bent connector terminals causing low-resistance path to ground
- Faulty body control / window control module or grounding point
- Water ingress in door causing short circuits
Symptoms
- Front left window will not lower (or lower only intermittently)
- Window control may be inoperative in the door switch but work from master switch (or vice versa)
- Blown fuse or repeated fuse failures on the window circuit
- Diagnostic trouble code B1406 present; possible abnormal behavior of other door electronics
- Occasional clicking or lack of motor response when switching to lower
What to check
- Verify stored freeze frame / live data for switch/wiring status with a scan tool
- Inspect fuses and relays for the power window circuit
- Visual inspection of door wiring harness through the door hinge boot for chafing
- Check connector at the front left window switch for corrosion, moisture, or bent pins
- Measure voltage at the switch connector with ignition ON (observe safety procedures)
Signal parameters
- Battery voltage at switch power terminal: ~12–14 V with ignition/accessory ON
- Switch output when not pressed: open/near battery voltage (depending on circuit design) — no direct 0 V to chassis ground
- Short-to-ground condition: near 0 V or full continuity to chassis ground on the switch signal line
- Motor current draw when operating: typically several amps (varies by motor); excessive current suggests mechanical bind or short
- Resistance: continuity between the signal/return wire and chassis ground indicates short (low ohms)
Diagnostic algorithm
- Read and record freeze-frame and live data with a diagnostic scanner. Confirm B1406 and any related codes.
- Turn ignition OFF, remove the key, and disconnect battery negative if you will be unplugging connectors or accessing terminals.
- Visually inspect the door harness where it enters the body (rubber boot). Look for broken wires, pinching, or exposed conductors.
- Unplug the front left window switch connector. With ignition ON, measure voltage between the switch power terminal and ground to confirm supply voltage.
- With connector unplugged, check continuity between the suspected switch signal/ground wire and chassis ground. Low resistance indicates a short to ground.
- If short present at connector, isolate by back-probing or disconnecting sections of wiring (door vs body harness) to locate the short area (door harness, boot, or body side).
- Inspect and if necessary remove the switch from the door. Bench-test the switch for internal shorts using a multimeter across terminals while operating the switch.
- Repair damaged wiring (replace or solder and insulate, replace grommet/boot), clean/repair corroded connectors, or replace the switch assembly as indicated.
- After repair, clear codes and retest operation multiple cycles. Monitor for code return and verify proper window function.
- If wiring and switch check OK but code persists, test/inspect the body control/window module grounds and outputs; consider module fault and consult service manual for advanced testing.
Likely causes
- Frayed or pinched harness where the door wiring passes through the hinge/boot
- Short inside the switch assembly (common after spill or wear)
- Connector plug at the switch has corrosion, bent pins or back-pin to ground
- Aftermarket accessory or previous repair damaged the wiring
- Poor/loose ground at door or body ground strap
Fault status
Status
Front left power window lowering switch circuit: short to ground detected.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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Code
B1406
LAND ROVER
B — Body
Auxiliary fuel heater
Views:
UK: 1
EN: 5
RU: 10
AI status
Completed
Completed
100%
Causes
- Damaged wiring with insulation breach contacting chassis ground
- Defective front left window switch (internal short)
- Corroded or bent connector terminals causing low-resistance path to ground
- Faulty body control / window control module or grounding point
- Water ingress in door causing short circuits
Symptoms
- Front left window will not lower (or lower only intermittently)
- Window control may be inoperative in the door switch but work from master switch (or vice versa)
- Blown fuse or repeated fuse failures on the window circuit
- Diagnostic trouble code B1406 present; possible abnormal behavior of other door electronics
- Occasional clicking or lack of motor response when switching to lower
What to check
- Verify stored freeze frame / live data for switch/wiring status with a scan tool
- Inspect fuses and relays for the power window circuit
- Visual inspection of door wiring harness through the door hinge boot for chafing
- Check connector at the front left window switch for corrosion, moisture, or bent pins
- Measure voltage at the switch connector with ignition ON (observe safety procedures)
Signal parameters
- Battery voltage at switch power terminal: ~12–14 V with ignition/accessory ON
- Switch output when not pressed: open/near battery voltage (depending on circuit design) — no direct 0 V to chassis ground
- Short-to-ground condition: near 0 V or full continuity to chassis ground on the switch signal line
- Motor current draw when operating: typically several amps (varies by motor); excessive current suggests mechanical bind or short
- Resistance: continuity between the signal/return wire and chassis ground indicates short (low ohms)
Diagnostic algorithm
- Read and record freeze-frame and live data with a diagnostic scanner. Confirm B1406 and any related codes.
- Turn ignition OFF, remove the key, and disconnect battery negative if you will be unplugging connectors or accessing terminals.
- Visually inspect the door harness where it enters the body (rubber boot). Look for broken wires, pinching, or exposed conductors.
- Unplug the front left window switch connector. With ignition ON, measure voltage between the switch power terminal and ground to confirm supply voltage.
- With connector unplugged, check continuity between the suspected switch signal/ground wire and chassis ground. Low resistance indicates a short to ground.
- If short present at connector, isolate by back-probing or disconnecting sections of wiring (door vs body harness) to locate the short area (door harness, boot, or body side).
- Inspect and if necessary remove the switch from the door. Bench-test the switch for internal shorts using a multimeter across terminals while operating the switch.
- Repair damaged wiring (replace or solder and insulate, replace grommet/boot), clean/repair corroded connectors, or replace the switch assembly as indicated.
- After repair, clear codes and retest operation multiple cycles. Monitor for code return and verify proper window function.
- If wiring and switch check OK but code persists, test/inspect the body control/window module grounds and outputs; consider module fault and consult service manual for advanced testing.
Likely causes
- Frayed or pinched harness where the door wiring passes through the hinge/boot
- Short inside the switch assembly (common after spill or wear)
- Connector plug at the switch has corrosion, bent pins or back-pin to ground
- Aftermarket accessory or previous repair damaged the wiring
- Poor/loose ground at door or body ground strap
Fault status
Status
Front left power window lowering switch circuit: short to ground detected.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
3
Land Rover Defender 300Tdi — Workshop Manual (1996 model year)
Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
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Code
B1406
MITSUBISHI
B — Body
FR analog G sensor fail
Views:
UK: 3
EN: 8
RU: 14
AI status
Completed
Completed
100%
Causes
- Damaged wiring with insulation breach contacting chassis ground
- Defective front left window switch (internal short)
- Corroded or bent connector terminals causing low-resistance path to ground
- Faulty body control / window control module or grounding point
- Water ingress in door causing short circuits
Symptoms
- Front left window will not lower (or lower only intermittently)
- Window control may be inoperative in the door switch but work from master switch (or vice versa)
- Blown fuse or repeated fuse failures on the window circuit
- Diagnostic trouble code B1406 present; possible abnormal behavior of other door electronics
- Occasional clicking or lack of motor response when switching to lower
What to check
- Verify stored freeze frame / live data for switch/wiring status with a scan tool
- Inspect fuses and relays for the power window circuit
- Visual inspection of door wiring harness through the door hinge boot for chafing
- Check connector at the front left window switch for corrosion, moisture, or bent pins
- Measure voltage at the switch connector with ignition ON (observe safety procedures)
Signal parameters
- Battery voltage at switch power terminal: ~12–14 V with ignition/accessory ON
- Switch output when not pressed: open/near battery voltage (depending on circuit design) — no direct 0 V to chassis ground
- Short-to-ground condition: near 0 V or full continuity to chassis ground on the switch signal line
- Motor current draw when operating: typically several amps (varies by motor); excessive current suggests mechanical bind or short
- Resistance: continuity between the signal/return wire and chassis ground indicates short (low ohms)
Diagnostic algorithm
- Read and record freeze-frame and live data with a diagnostic scanner. Confirm B1406 and any related codes.
- Turn ignition OFF, remove the key, and disconnect battery negative if you will be unplugging connectors or accessing terminals.
- Visually inspect the door harness where it enters the body (rubber boot). Look for broken wires, pinching, or exposed conductors.
- Unplug the front left window switch connector. With ignition ON, measure voltage between the switch power terminal and ground to confirm supply voltage.
- With connector unplugged, check continuity between the suspected switch signal/ground wire and chassis ground. Low resistance indicates a short to ground.
- If short present at connector, isolate by back-probing or disconnecting sections of wiring (door vs body harness) to locate the short area (door harness, boot, or body side).
- Inspect and if necessary remove the switch from the door. Bench-test the switch for internal shorts using a multimeter across terminals while operating the switch.
- Repair damaged wiring (replace or solder and insulate, replace grommet/boot), clean/repair corroded connectors, or replace the switch assembly as indicated.
- After repair, clear codes and retest operation multiple cycles. Monitor for code return and verify proper window function.
- If wiring and switch check OK but code persists, test/inspect the body control/window module grounds and outputs; consider module fault and consult service manual for advanced testing.
Likely causes
- Frayed or pinched harness where the door wiring passes through the hinge/boot
- Short inside the switch assembly (common after spill or wear)
- Connector plug at the switch has corrosion, bent pins or back-pin to ground
- Aftermarket accessory or previous repair damaged the wiring
- Poor/loose ground at door or body ground strap
Fault status
Status
Front left power window lowering switch circuit: short to ground detected.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
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+100 karma for a short comment :)
Was this AI description helpful?
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0
Send to email
Code
B1406
Other
B — Body
Driver Power Window Down Circuit Short To Ground
Views:
UK: 10
EN: 15
RU: 28
AI status
Completed
Completed
100%
Causes
- Damaged wiring with insulation breach contacting chassis ground
- Defective front left window switch (internal short)
- Corroded or bent connector terminals causing low-resistance path to ground
- Faulty body control / window control module or grounding point
- Water ingress in door causing short circuits
Symptoms
- Front left window will not lower (or lower only intermittently)
- Window control may be inoperative in the door switch but work from master switch (or vice versa)
- Blown fuse or repeated fuse failures on the window circuit
- Diagnostic trouble code B1406 present; possible abnormal behavior of other door electronics
- Occasional clicking or lack of motor response when switching to lower
What to check
- Verify stored freeze frame / live data for switch/wiring status with a scan tool
- Inspect fuses and relays for the power window circuit
- Visual inspection of door wiring harness through the door hinge boot for chafing
- Check connector at the front left window switch for corrosion, moisture, or bent pins
- Measure voltage at the switch connector with ignition ON (observe safety procedures)
Signal parameters
- Battery voltage at switch power terminal: ~12–14 V with ignition/accessory ON
- Switch output when not pressed: open/near battery voltage (depending on circuit design) — no direct 0 V to chassis ground
- Short-to-ground condition: near 0 V or full continuity to chassis ground on the switch signal line
- Motor current draw when operating: typically several amps (varies by motor); excessive current suggests mechanical bind or short
- Resistance: continuity between the signal/return wire and chassis ground indicates short (low ohms)
Diagnostic algorithm
- Read and record freeze-frame and live data with a diagnostic scanner. Confirm B1406 and any related codes.
- Turn ignition OFF, remove the key, and disconnect battery negative if you will be unplugging connectors or accessing terminals.
- Visually inspect the door harness where it enters the body (rubber boot). Look for broken wires, pinching, or exposed conductors.
- Unplug the front left window switch connector. With ignition ON, measure voltage between the switch power terminal and ground to confirm supply voltage.
- With connector unplugged, check continuity between the suspected switch signal/ground wire and chassis ground. Low resistance indicates a short to ground.
- If short present at connector, isolate by back-probing or disconnecting sections of wiring (door vs body harness) to locate the short area (door harness, boot, or body side).
- Inspect and if necessary remove the switch from the door. Bench-test the switch for internal shorts using a multimeter across terminals while operating the switch.
- Repair damaged wiring (replace or solder and insulate, replace grommet/boot), clean/repair corroded connectors, or replace the switch assembly as indicated.
- After repair, clear codes and retest operation multiple cycles. Monitor for code return and verify proper window function.
- If wiring and switch check OK but code persists, test/inspect the body control/window module grounds and outputs; consider module fault and consult service manual for advanced testing.
Likely causes
- Frayed or pinched harness where the door wiring passes through the hinge/boot
- Short inside the switch assembly (common after spill or wear)
- Connector plug at the switch has corrosion, bent pins or back-pin to ground
- Aftermarket accessory or previous repair damaged the wiring
- Poor/loose ground at door or body ground strap
Fault status
Status
Front left power window lowering switch circuit: short to ground detected.
Repair difficulty: Medium
Diagnostic time: 0.5-2.0 hours
Similar codes
Workshop Manuals
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Workshop ManualLand Rover Defender Workshop Manual Supplement & Body Repair Manual (1999 & 2002 MY)
Workshop ManualLand Rover Range Rover — Electrical Library (LRL 0453ENG, 2002)
Workshop ManualYour experience will help others
+100 karma for a short comment :)
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