Code
B1421
ALFA ROMEO
B — Body
Front right electric window motor short to ground
Views:
UK: 5
EN: 10
RU: 4
AI status
Completed
Completed
100%
Causes
- Damaged wiring harness (chafing, pinched cable) causing insulation breach to chassis ground
- Corroded or loose connector at the front right window motor or switch
- Internal short in the window motor armature or brushes
- Failed window regulator or mechanical binding causing overload and electrical fault
- Faulty window switch or body control module (incorrect output driver)
- Water ingress into connector or motor
Symptoms
- Front right window will not operate or operates intermittently
- Blown fuse or circuit breaker related to windows
- Burnt smell near door or window motor area
- Error lamp or message on dash related to windows or body electronics
- DTC B1421 stored in the body control module or window control module
What to check
- Read and record freeze frame and related DTCs with a scan tool; clear and see if fault returns
- Visual inspection of connector, pins and wiring along door hinge/boot and inside door
- Check fuse and any circuit protection for the window circuit
- Measure voltage and polarity at the motor connector while commanding the window
- Measure resistance between motor power terminals and chassis ground with ignition off
- Swap/simulate with known-good motor or switch where applicable (for diagnosis only)
Signal parameters
- Battery voltage (~11.5–14.5 V) present at motor feed when commanded (direction dependent)
- When module not commanding, motor feed should be high-impedance; a short to ground will show near 0 V or continuity to chassis ground
- Motor coil DC resistance typically low (approximately 0.5–10 ohms depending on model); a near 0 ohm reading to chassis indicates short
- Current draw during operation normally hundreds of mA to several amps; excessively high current suggests internal short or mechanical binding
Diagnostic algorithm
- Retrieve DTCs and related data with scan tool; note freeze frame and any other window/body codes.
- Visually inspect the front right door wiring from the body harness through the door boot to the motor and switch; look for chafing, cuts, or crushed sections.
- Inspect motor and connector for corrosion, water, burnt pins or melted insulation; repair or replace connector as needed.
- With ignition off, disconnect the motor connector and measure resistance between each motor terminal and chassis ground. A near-zero reading indicates a short to ground in the motor or wiring.
- With the connector disconnected, check continuity from the module output pin to chassis ground. If continuity exists at the module connector, the short is in the wiring or module.
- With assistance, command the window up/down while probing the motor connector (or module output) with a multimeter/oscilloscope to verify proper voltage switching. Use caution—motor will move.
- If wiring and connector are good, bench-test the motor by applying 12 V directly (observe polarity for direction). Excessive current or no movement indicates a motor fault—replace motor.
- If motor tests good and wiring is intact, test or replace the window switch and, if necessary, the body/window control module following manufacturer procedures.
- After repairs, clear DTCs and perform several full up/down operations to confirm the fault does not return.
Likely causes
- Wiring chafe at door hinge/boot where harness flexes (very common)
- Corroded/contaminated motor connector or pins
- Motor internal short or seized bearings causing abnormal current
- Switch or BCM output stage fault (less common, after wiring/motor checks)
Fault status
Status
Front right window motor circuit - short to ground detected by body/window control module.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
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Code
B1421
FIAT
B — Body
Front right electric window motor short to ground
Views:
UK: 6
EN: 9
RU: 4
AI status
Completed
Completed
100%
Causes
- Damaged wiring harness (chafing, pinched cable) causing insulation breach to chassis ground
- Corroded or loose connector at the front right window motor or switch
- Internal short in the window motor armature or brushes
- Failed window regulator or mechanical binding causing overload and electrical fault
- Faulty window switch or body control module (incorrect output driver)
- Water ingress into connector or motor
Symptoms
- Front right window will not operate or operates intermittently
- Blown fuse or circuit breaker related to windows
- Burnt smell near door or window motor area
- Error lamp or message on dash related to windows or body electronics
- DTC B1421 stored in the body control module or window control module
What to check
- Read and record freeze frame and related DTCs with a scan tool; clear and see if fault returns
- Visual inspection of connector, pins and wiring along door hinge/boot and inside door
- Check fuse and any circuit protection for the window circuit
- Measure voltage and polarity at the motor connector while commanding the window
- Measure resistance between motor power terminals and chassis ground with ignition off
- Swap/simulate with known-good motor or switch where applicable (for diagnosis only)
Signal parameters
- Battery voltage (~11.5–14.5 V) present at motor feed when commanded (direction dependent)
- When module not commanding, motor feed should be high-impedance; a short to ground will show near 0 V or continuity to chassis ground
- Motor coil DC resistance typically low (approximately 0.5–10 ohms depending on model); a near 0 ohm reading to chassis indicates short
- Current draw during operation normally hundreds of mA to several amps; excessively high current suggests internal short or mechanical binding
Diagnostic algorithm
- Retrieve DTCs and related data with scan tool; note freeze frame and any other window/body codes.
- Visually inspect the front right door wiring from the body harness through the door boot to the motor and switch; look for chafing, cuts, or crushed sections.
- Inspect motor and connector for corrosion, water, burnt pins or melted insulation; repair or replace connector as needed.
- With ignition off, disconnect the motor connector and measure resistance between each motor terminal and chassis ground. A near-zero reading indicates a short to ground in the motor or wiring.
- With the connector disconnected, check continuity from the module output pin to chassis ground. If continuity exists at the module connector, the short is in the wiring or module.
- With assistance, command the window up/down while probing the motor connector (or module output) with a multimeter/oscilloscope to verify proper voltage switching. Use caution—motor will move.
- If wiring and connector are good, bench-test the motor by applying 12 V directly (observe polarity for direction). Excessive current or no movement indicates a motor fault—replace motor.
- If motor tests good and wiring is intact, test or replace the window switch and, if necessary, the body/window control module following manufacturer procedures.
- After repairs, clear DTCs and perform several full up/down operations to confirm the fault does not return.
Likely causes
- Wiring chafe at door hinge/boot where harness flexes (very common)
- Corroded/contaminated motor connector or pins
- Motor internal short or seized bearings causing abnormal current
- Switch or BCM output stage fault (less common, after wiring/motor checks)
Fault status
Status
Front right window motor circuit - short to ground detected by body/window control module.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
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Code
B1421
LAND ROVER
B — Body
Left front - Climate seat - Electric thermal device 2
Views:
UK: 8
EN: 12
RU: 9
AI status
Completed
Completed
100%
Causes
- Damaged wiring harness (chafing, pinched cable) causing insulation breach to chassis ground
- Corroded or loose connector at the front right window motor or switch
- Internal short in the window motor armature or brushes
- Failed window regulator or mechanical binding causing overload and electrical fault
- Faulty window switch or body control module (incorrect output driver)
- Water ingress into connector or motor
Symptoms
- Front right window will not operate or operates intermittently
- Blown fuse or circuit breaker related to windows
- Burnt smell near door or window motor area
- Error lamp or message on dash related to windows or body electronics
- DTC B1421 stored in the body control module or window control module
What to check
- Read and record freeze frame and related DTCs with a scan tool; clear and see if fault returns
- Visual inspection of connector, pins and wiring along door hinge/boot and inside door
- Check fuse and any circuit protection for the window circuit
- Measure voltage and polarity at the motor connector while commanding the window
- Measure resistance between motor power terminals and chassis ground with ignition off
- Swap/simulate with known-good motor or switch where applicable (for diagnosis only)
Signal parameters
- Battery voltage (~11.5–14.5 V) present at motor feed when commanded (direction dependent)
- When module not commanding, motor feed should be high-impedance; a short to ground will show near 0 V or continuity to chassis ground
- Motor coil DC resistance typically low (approximately 0.5–10 ohms depending on model); a near 0 ohm reading to chassis indicates short
- Current draw during operation normally hundreds of mA to several amps; excessively high current suggests internal short or mechanical binding
Diagnostic algorithm
- Retrieve DTCs and related data with scan tool; note freeze frame and any other window/body codes.
- Visually inspect the front right door wiring from the body harness through the door boot to the motor and switch; look for chafing, cuts, or crushed sections.
- Inspect motor and connector for corrosion, water, burnt pins or melted insulation; repair or replace connector as needed.
- With ignition off, disconnect the motor connector and measure resistance between each motor terminal and chassis ground. A near-zero reading indicates a short to ground in the motor or wiring.
- With the connector disconnected, check continuity from the module output pin to chassis ground. If continuity exists at the module connector, the short is in the wiring or module.
- With assistance, command the window up/down while probing the motor connector (or module output) with a multimeter/oscilloscope to verify proper voltage switching. Use caution—motor will move.
- If wiring and connector are good, bench-test the motor by applying 12 V directly (observe polarity for direction). Excessive current or no movement indicates a motor fault—replace motor.
- If motor tests good and wiring is intact, test or replace the window switch and, if necessary, the body/window control module following manufacturer procedures.
- After repairs, clear DTCs and perform several full up/down operations to confirm the fault does not return.
Likely causes
- Wiring chafe at door hinge/boot where harness flexes (very common)
- Corroded/contaminated motor connector or pins
- Motor internal short or seized bearings causing abnormal current
- Switch or BCM output stage fault (less common, after wiring/motor checks)
Fault status
Status
Front right window motor circuit - short to ground detected by body/window control module.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
Similar codes
Workshop Manuals
Repair manuals for LAND ROVER
1
Land Rover Defender Workshop Manual 1999-2002 MY
Workshop ManualYour experience will help others
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Code
B1421
MERCEDES-BENZ
B — Body
Pulse module (N05)
Views:
UK: 16
EN: 21
RU: 12
AI status
Completed
Completed
100%
Causes
- Damaged wiring harness (chafing, pinched cable) causing insulation breach to chassis ground
- Corroded or loose connector at the front right window motor or switch
- Internal short in the window motor armature or brushes
- Failed window regulator or mechanical binding causing overload and electrical fault
- Faulty window switch or body control module (incorrect output driver)
- Water ingress into connector or motor
Symptoms
- Front right window will not operate or operates intermittently
- Blown fuse or circuit breaker related to windows
- Burnt smell near door or window motor area
- Error lamp or message on dash related to windows or body electronics
- DTC B1421 stored in the body control module or window control module
What to check
- Read and record freeze frame and related DTCs with a scan tool; clear and see if fault returns
- Visual inspection of connector, pins and wiring along door hinge/boot and inside door
- Check fuse and any circuit protection for the window circuit
- Measure voltage and polarity at the motor connector while commanding the window
- Measure resistance between motor power terminals and chassis ground with ignition off
- Swap/simulate with known-good motor or switch where applicable (for diagnosis only)
Signal parameters
- Battery voltage (~11.5–14.5 V) present at motor feed when commanded (direction dependent)
- When module not commanding, motor feed should be high-impedance; a short to ground will show near 0 V or continuity to chassis ground
- Motor coil DC resistance typically low (approximately 0.5–10 ohms depending on model); a near 0 ohm reading to chassis indicates short
- Current draw during operation normally hundreds of mA to several amps; excessively high current suggests internal short or mechanical binding
Diagnostic algorithm
- Retrieve DTCs and related data with scan tool; note freeze frame and any other window/body codes.
- Visually inspect the front right door wiring from the body harness through the door boot to the motor and switch; look for chafing, cuts, or crushed sections.
- Inspect motor and connector for corrosion, water, burnt pins or melted insulation; repair or replace connector as needed.
- With ignition off, disconnect the motor connector and measure resistance between each motor terminal and chassis ground. A near-zero reading indicates a short to ground in the motor or wiring.
- With the connector disconnected, check continuity from the module output pin to chassis ground. If continuity exists at the module connector, the short is in the wiring or module.
- With assistance, command the window up/down while probing the motor connector (or module output) with a multimeter/oscilloscope to verify proper voltage switching. Use caution—motor will move.
- If wiring and connector are good, bench-test the motor by applying 12 V directly (observe polarity for direction). Excessive current or no movement indicates a motor fault—replace motor.
- If motor tests good and wiring is intact, test or replace the window switch and, if necessary, the body/window control module following manufacturer procedures.
- After repairs, clear DTCs and perform several full up/down operations to confirm the fault does not return.
Likely causes
- Wiring chafe at door hinge/boot where harness flexes (very common)
- Corroded/contaminated motor connector or pins
- Motor internal short or seized bearings causing abnormal current
- Switch or BCM output stage fault (less common, after wiring/motor checks)
Fault status
Status
Front right window motor circuit - short to ground detected by body/window control module.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
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Code
B1421
MITSUBISHI
B — Body
FR side ABG squib open
Views:
UK: 10
EN: 16
RU: 9
AI status
Completed
Completed
100%
Causes
- Damaged wiring harness (chafing, pinched cable) causing insulation breach to chassis ground
- Corroded or loose connector at the front right window motor or switch
- Internal short in the window motor armature or brushes
- Failed window regulator or mechanical binding causing overload and electrical fault
- Faulty window switch or body control module (incorrect output driver)
- Water ingress into connector or motor
Symptoms
- Front right window will not operate or operates intermittently
- Blown fuse or circuit breaker related to windows
- Burnt smell near door or window motor area
- Error lamp or message on dash related to windows or body electronics
- DTC B1421 stored in the body control module or window control module
What to check
- Read and record freeze frame and related DTCs with a scan tool; clear and see if fault returns
- Visual inspection of connector, pins and wiring along door hinge/boot and inside door
- Check fuse and any circuit protection for the window circuit
- Measure voltage and polarity at the motor connector while commanding the window
- Measure resistance between motor power terminals and chassis ground with ignition off
- Swap/simulate with known-good motor or switch where applicable (for diagnosis only)
Signal parameters
- Battery voltage (~11.5–14.5 V) present at motor feed when commanded (direction dependent)
- When module not commanding, motor feed should be high-impedance; a short to ground will show near 0 V or continuity to chassis ground
- Motor coil DC resistance typically low (approximately 0.5–10 ohms depending on model); a near 0 ohm reading to chassis indicates short
- Current draw during operation normally hundreds of mA to several amps; excessively high current suggests internal short or mechanical binding
Diagnostic algorithm
- Retrieve DTCs and related data with scan tool; note freeze frame and any other window/body codes.
- Visually inspect the front right door wiring from the body harness through the door boot to the motor and switch; look for chafing, cuts, or crushed sections.
- Inspect motor and connector for corrosion, water, burnt pins or melted insulation; repair or replace connector as needed.
- With ignition off, disconnect the motor connector and measure resistance between each motor terminal and chassis ground. A near-zero reading indicates a short to ground in the motor or wiring.
- With the connector disconnected, check continuity from the module output pin to chassis ground. If continuity exists at the module connector, the short is in the wiring or module.
- With assistance, command the window up/down while probing the motor connector (or module output) with a multimeter/oscilloscope to verify proper voltage switching. Use caution—motor will move.
- If wiring and connector are good, bench-test the motor by applying 12 V directly (observe polarity for direction). Excessive current or no movement indicates a motor fault—replace motor.
- If motor tests good and wiring is intact, test or replace the window switch and, if necessary, the body/window control module following manufacturer procedures.
- After repairs, clear DTCs and perform several full up/down operations to confirm the fault does not return.
Likely causes
- Wiring chafe at door hinge/boot where harness flexes (very common)
- Corroded/contaminated motor connector or pins
- Motor internal short or seized bearings causing abnormal current
- Switch or BCM output stage fault (less common, after wiring/motor checks)
Fault status
Status
Front right window motor circuit - short to ground detected by body/window control module.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
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Code
B1421
OPEL
B — Body
Power Supply Signal Range/Performance
Views:
UK: 6
EN: 9
RU: 5
AI status
Completed
Completed
100%
Causes
- Damaged wiring harness (chafing, pinched cable) causing insulation breach to chassis ground
- Corroded or loose connector at the front right window motor or switch
- Internal short in the window motor armature or brushes
- Failed window regulator or mechanical binding causing overload and electrical fault
- Faulty window switch or body control module (incorrect output driver)
- Water ingress into connector or motor
Symptoms
- Front right window will not operate or operates intermittently
- Blown fuse or circuit breaker related to windows
- Burnt smell near door or window motor area
- Error lamp or message on dash related to windows or body electronics
- DTC B1421 stored in the body control module or window control module
What to check
- Read and record freeze frame and related DTCs with a scan tool; clear and see if fault returns
- Visual inspection of connector, pins and wiring along door hinge/boot and inside door
- Check fuse and any circuit protection for the window circuit
- Measure voltage and polarity at the motor connector while commanding the window
- Measure resistance between motor power terminals and chassis ground with ignition off
- Swap/simulate with known-good motor or switch where applicable (for diagnosis only)
Signal parameters
- Battery voltage (~11.5–14.5 V) present at motor feed when commanded (direction dependent)
- When module not commanding, motor feed should be high-impedance; a short to ground will show near 0 V or continuity to chassis ground
- Motor coil DC resistance typically low (approximately 0.5–10 ohms depending on model); a near 0 ohm reading to chassis indicates short
- Current draw during operation normally hundreds of mA to several amps; excessively high current suggests internal short or mechanical binding
Diagnostic algorithm
- Retrieve DTCs and related data with scan tool; note freeze frame and any other window/body codes.
- Visually inspect the front right door wiring from the body harness through the door boot to the motor and switch; look for chafing, cuts, or crushed sections.
- Inspect motor and connector for corrosion, water, burnt pins or melted insulation; repair or replace connector as needed.
- With ignition off, disconnect the motor connector and measure resistance between each motor terminal and chassis ground. A near-zero reading indicates a short to ground in the motor or wiring.
- With the connector disconnected, check continuity from the module output pin to chassis ground. If continuity exists at the module connector, the short is in the wiring or module.
- With assistance, command the window up/down while probing the motor connector (or module output) with a multimeter/oscilloscope to verify proper voltage switching. Use caution—motor will move.
- If wiring and connector are good, bench-test the motor by applying 12 V directly (observe polarity for direction). Excessive current or no movement indicates a motor fault—replace motor.
- If motor tests good and wiring is intact, test or replace the window switch and, if necessary, the body/window control module following manufacturer procedures.
- After repairs, clear DTCs and perform several full up/down operations to confirm the fault does not return.
Likely causes
- Wiring chafe at door hinge/boot where harness flexes (very common)
- Corroded/contaminated motor connector or pins
- Motor internal short or seized bearings causing abnormal current
- Switch or BCM output stage fault (less common, after wiring/motor checks)
Fault status
Status
Front right window motor circuit - short to ground detected by body/window control module.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
Similar codes
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Code
B1421
Other
B — Body
Passenger Power Window Motor Circuit Short To Ground
Views:
UK: 24
EN: 30
RU: 21
AI status
Completed
Completed
100%
Causes
- Damaged wiring harness (chafing, pinched cable) causing insulation breach to chassis ground
- Corroded or loose connector at the front right window motor or switch
- Internal short in the window motor armature or brushes
- Failed window regulator or mechanical binding causing overload and electrical fault
- Faulty window switch or body control module (incorrect output driver)
- Water ingress into connector or motor
Symptoms
- Front right window will not operate or operates intermittently
- Blown fuse or circuit breaker related to windows
- Burnt smell near door or window motor area
- Error lamp or message on dash related to windows or body electronics
- DTC B1421 stored in the body control module or window control module
What to check
- Read and record freeze frame and related DTCs with a scan tool; clear and see if fault returns
- Visual inspection of connector, pins and wiring along door hinge/boot and inside door
- Check fuse and any circuit protection for the window circuit
- Measure voltage and polarity at the motor connector while commanding the window
- Measure resistance between motor power terminals and chassis ground with ignition off
- Swap/simulate with known-good motor or switch where applicable (for diagnosis only)
Signal parameters
- Battery voltage (~11.5–14.5 V) present at motor feed when commanded (direction dependent)
- When module not commanding, motor feed should be high-impedance; a short to ground will show near 0 V or continuity to chassis ground
- Motor coil DC resistance typically low (approximately 0.5–10 ohms depending on model); a near 0 ohm reading to chassis indicates short
- Current draw during operation normally hundreds of mA to several amps; excessively high current suggests internal short or mechanical binding
Diagnostic algorithm
- Retrieve DTCs and related data with scan tool; note freeze frame and any other window/body codes.
- Visually inspect the front right door wiring from the body harness through the door boot to the motor and switch; look for chafing, cuts, or crushed sections.
- Inspect motor and connector for corrosion, water, burnt pins or melted insulation; repair or replace connector as needed.
- With ignition off, disconnect the motor connector and measure resistance between each motor terminal and chassis ground. A near-zero reading indicates a short to ground in the motor or wiring.
- With the connector disconnected, check continuity from the module output pin to chassis ground. If continuity exists at the module connector, the short is in the wiring or module.
- With assistance, command the window up/down while probing the motor connector (or module output) with a multimeter/oscilloscope to verify proper voltage switching. Use caution—motor will move.
- If wiring and connector are good, bench-test the motor by applying 12 V directly (observe polarity for direction). Excessive current or no movement indicates a motor fault—replace motor.
- If motor tests good and wiring is intact, test or replace the window switch and, if necessary, the body/window control module following manufacturer procedures.
- After repairs, clear DTCs and perform several full up/down operations to confirm the fault does not return.
Likely causes
- Wiring chafe at door hinge/boot where harness flexes (very common)
- Corroded/contaminated motor connector or pins
- Motor internal short or seized bearings causing abnormal current
- Switch or BCM output stage fault (less common, after wiring/motor checks)
Fault status
Status
Front right window motor circuit - short to ground detected by body/window control module.
Repair difficulty: Medium
Diagnostic time: 0.5-2 hours
Similar codes
Workshop Manuals
Available brands with manuals
1
LAND ROVER 1
Land Rover Defender Workshop Manual 1999-2002 MY
Workshop ManualYour experience will help others
+100 karma for a short comment :)
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