B1290

Code

ALFA ROMEO B — Body

Right air intake potentiometer servo short to positive

Brand: ALFA ROMEO

Type: B — Body

Views: UK: 17 EN: 23 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged or pinched wiring harness causing short to +12V
Corroded/damaged connector or terminal with battery voltage contact
Failed potentiometer/servo assembly with internal short
Faulty body control/HVAC control module output or internal short
Aftermarket accessories or repairs that disturbed wiring

Symptoms

HVAC right air intake flap does not move or moves erratically
Right-side vent temperature or airflow not controllable
HVAC control module stores B1290 and may disable certain climate functions
Audible clicking from servo or no servo movement
Fuse may blow intermittently if short is severe

What to check

Read and record freeze frame and live data with a diagnostic scan tool (command flap/monitor potentiometer voltage)
Visually inspect right intake servo connector and wiring harness for damage, corrosion, pinched wires or recent repair areas
With ignition ON (engine off where required), back-probe the potentiometer connector: measure reference, signal and ground voltages
Check for short to +12V on the signal wire (measure voltage with servo disconnected)
Measure continuity between signal wire and fused +12V to confirm short (key OFF)
Inspect fuses and related HVAC relays for faults

Signal parameters

Reference (supply) voltage: approx. 5 V (present with ignition ON)
Potentiometer signal voltage: variable with flap position, typically ~0.5–4.5 V
Short condition: signal measures near battery voltage (~12 V) when shorted to positive
Ground continuity: signal return should share a common ground with control module (
Open circuit: very high resistance/OL on signal or supply indicates open rather than short

Diagnostic algorithm

Connect a OEM-capable scan tool, read DTCs and view live data for the right intake potentiometer signal while commanding flap movement.
Visually inspect the right HVAC actuator, connector and harness routing for physical damage, melted insulation, or aftermarket modifications.
With ignition ON, back-probe the actuator connector: verify reference voltage (~5 V), ground and signal voltage. Note if signal is stuck at battery voltage (~12 V).
Turn ignition OFF. Disconnect the servo connector. Measure resistance between the signal pin and battery +12 V. A low resistance indicates a short to positive in wiring or connector.
If wiring appears intact, bench-test or swap the servo with a known-good unit to determine whether the fault follows the actuator.
If fault remains with good actuator, trace and repair wiring harness: isolate and repair short (repair or replace damaged section, protect harness routing).
After repairs, clear codes and re-test HVAC operation and live data; cycle ignition and command flap through full travel to confirm proper signal range.
If wiring and actuator test good but fault persists, inspect/replace the HVAC control/body control module as a last resort (verify with manufacturer-guided diagnostics).

Likely causes

Chafed wiring contacting a fused +12V feed near HVAC harness
Connector terminal pushed into contact with +12V source or corrosion bridging contacts
Internal short inside the right intake potentiometer/servo unit

Fault status

⚠️ Status

Right air intake potentiometer servo signal circuit shorted to battery positive voltage detected by HVAC control system.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours

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Code

B1290

FIAT B — Body

Right air intake potentiometer servo short to positive

Brand: FIAT

Type: B — Body

Views: UK: 15 EN: 24 RU: 19

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged or pinched wiring harness causing short to +12V
Corroded/damaged connector or terminal with battery voltage contact
Failed potentiometer/servo assembly with internal short
Faulty body control/HVAC control module output or internal short
Aftermarket accessories or repairs that disturbed wiring

Symptoms

HVAC right air intake flap does not move or moves erratically
Right-side vent temperature or airflow not controllable
HVAC control module stores B1290 and may disable certain climate functions
Audible clicking from servo or no servo movement
Fuse may blow intermittently if short is severe

What to check

Read and record freeze frame and live data with a diagnostic scan tool (command flap/monitor potentiometer voltage)
Visually inspect right intake servo connector and wiring harness for damage, corrosion, pinched wires or recent repair areas
With ignition ON (engine off where required), back-probe the potentiometer connector: measure reference, signal and ground voltages
Check for short to +12V on the signal wire (measure voltage with servo disconnected)
Measure continuity between signal wire and fused +12V to confirm short (key OFF)
Inspect fuses and related HVAC relays for faults

Signal parameters

Reference (supply) voltage: approx. 5 V (present with ignition ON)
Potentiometer signal voltage: variable with flap position, typically ~0.5–4.5 V
Short condition: signal measures near battery voltage (~12 V) when shorted to positive
Ground continuity: signal return should share a common ground with control module (
Open circuit: very high resistance/OL on signal or supply indicates open rather than short

Diagnostic algorithm

Connect a OEM-capable scan tool, read DTCs and view live data for the right intake potentiometer signal while commanding flap movement.
Visually inspect the right HVAC actuator, connector and harness routing for physical damage, melted insulation, or aftermarket modifications.
With ignition ON, back-probe the actuator connector: verify reference voltage (~5 V), ground and signal voltage. Note if signal is stuck at battery voltage (~12 V).
Turn ignition OFF. Disconnect the servo connector. Measure resistance between the signal pin and battery +12 V. A low resistance indicates a short to positive in wiring or connector.
If wiring appears intact, bench-test or swap the servo with a known-good unit to determine whether the fault follows the actuator.
If fault remains with good actuator, trace and repair wiring harness: isolate and repair short (repair or replace damaged section, protect harness routing).
After repairs, clear codes and re-test HVAC operation and live data; cycle ignition and command flap through full travel to confirm proper signal range.
If wiring and actuator test good but fault persists, inspect/replace the HVAC control/body control module as a last resort (verify with manufacturer-guided diagnostics).

Likely causes

Chafed wiring contacting a fused +12V feed near HVAC harness
Connector terminal pushed into contact with +12V source or corrosion bridging contacts
Internal short inside the right intake potentiometer/servo unit

Fault status

⚠️ Status

Right air intake potentiometer servo signal circuit shorted to battery positive voltage detected by HVAC control system.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours

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Code

B1290

LAND ROVER B — Body

Speaker 19

Brand: LAND ROVER

Type: B — Body

Views: UK: 17 EN: 25 RU: 18

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged or pinched wiring harness causing short to +12V
Corroded/damaged connector or terminal with battery voltage contact
Failed potentiometer/servo assembly with internal short
Faulty body control/HVAC control module output or internal short
Aftermarket accessories or repairs that disturbed wiring

Symptoms

HVAC right air intake flap does not move or moves erratically
Right-side vent temperature or airflow not controllable
HVAC control module stores B1290 and may disable certain climate functions
Audible clicking from servo or no servo movement
Fuse may blow intermittently if short is severe

What to check

Read and record freeze frame and live data with a diagnostic scan tool (command flap/monitor potentiometer voltage)
Visually inspect right intake servo connector and wiring harness for damage, corrosion, pinched wires or recent repair areas
With ignition ON (engine off where required), back-probe the potentiometer connector: measure reference, signal and ground voltages
Check for short to +12V on the signal wire (measure voltage with servo disconnected)
Measure continuity between signal wire and fused +12V to confirm short (key OFF)
Inspect fuses and related HVAC relays for faults

Signal parameters

Reference (supply) voltage: approx. 5 V (present with ignition ON)
Potentiometer signal voltage: variable with flap position, typically ~0.5–4.5 V
Short condition: signal measures near battery voltage (~12 V) when shorted to positive
Ground continuity: signal return should share a common ground with control module (
Open circuit: very high resistance/OL on signal or supply indicates open rather than short

Diagnostic algorithm

Connect a OEM-capable scan tool, read DTCs and view live data for the right intake potentiometer signal while commanding flap movement.
Visually inspect the right HVAC actuator, connector and harness routing for physical damage, melted insulation, or aftermarket modifications.
With ignition ON, back-probe the actuator connector: verify reference voltage (~5 V), ground and signal voltage. Note if signal is stuck at battery voltage (~12 V).
Turn ignition OFF. Disconnect the servo connector. Measure resistance between the signal pin and battery +12 V. A low resistance indicates a short to positive in wiring or connector.
If wiring appears intact, bench-test or swap the servo with a known-good unit to determine whether the fault follows the actuator.
If fault remains with good actuator, trace and repair wiring harness: isolate and repair short (repair or replace damaged section, protect harness routing).
After repairs, clear codes and re-test HVAC operation and live data; cycle ignition and command flap through full travel to confirm proper signal range.
If wiring and actuator test good but fault persists, inspect/replace the HVAC control/body control module as a last resort (verify with manufacturer-guided diagnostics).

Likely causes

Chafed wiring contacting a fused +12V feed near HVAC harness
Connector terminal pushed into contact with +12V source or corrosion bridging contacts
Internal short inside the right intake potentiometer/servo unit

Fault status

⚠️ Status

Right air intake potentiometer servo signal circuit shorted to battery positive voltage detected by HVAC control system.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

Repair manuals

Manual library for LAND ROVER

160

Browse 160 LAND ROVER manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

LAND ROVER

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Code

B1290

Other B — Body

Servo Motor Potentiometer Airintake Right Circuit Short To Battery

Brand: Other

Type: B — Body

Views: UK: 21 EN: 35 RU: 30

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged or pinched wiring harness causing short to +12V
Corroded/damaged connector or terminal with battery voltage contact
Failed potentiometer/servo assembly with internal short
Faulty body control/HVAC control module output or internal short
Aftermarket accessories or repairs that disturbed wiring

Symptoms

HVAC right air intake flap does not move or moves erratically
Right-side vent temperature or airflow not controllable
HVAC control module stores B1290 and may disable certain climate functions
Audible clicking from servo or no servo movement
Fuse may blow intermittently if short is severe

What to check

Read and record freeze frame and live data with a diagnostic scan tool (command flap/monitor potentiometer voltage)
Visually inspect right intake servo connector and wiring harness for damage, corrosion, pinched wires or recent repair areas
With ignition ON (engine off where required), back-probe the potentiometer connector: measure reference, signal and ground voltages
Check for short to +12V on the signal wire (measure voltage with servo disconnected)
Measure continuity between signal wire and fused +12V to confirm short (key OFF)
Inspect fuses and related HVAC relays for faults

Signal parameters

Reference (supply) voltage: approx. 5 V (present with ignition ON)
Potentiometer signal voltage: variable with flap position, typically ~0.5–4.5 V
Short condition: signal measures near battery voltage (~12 V) when shorted to positive
Ground continuity: signal return should share a common ground with control module (
Open circuit: very high resistance/OL on signal or supply indicates open rather than short

Diagnostic algorithm

Connect a OEM-capable scan tool, read DTCs and view live data for the right intake potentiometer signal while commanding flap movement.
Visually inspect the right HVAC actuator, connector and harness routing for physical damage, melted insulation, or aftermarket modifications.
With ignition ON, back-probe the actuator connector: verify reference voltage (~5 V), ground and signal voltage. Note if signal is stuck at battery voltage (~12 V).
Turn ignition OFF. Disconnect the servo connector. Measure resistance between the signal pin and battery +12 V. A low resistance indicates a short to positive in wiring or connector.
If wiring appears intact, bench-test or swap the servo with a known-good unit to determine whether the fault follows the actuator.
If fault remains with good actuator, trace and repair wiring harness: isolate and repair short (repair or replace damaged section, protect harness routing).
After repairs, clear codes and re-test HVAC operation and live data; cycle ignition and command flap through full travel to confirm proper signal range.
If wiring and actuator test good but fault persists, inspect/replace the HVAC control/body control module as a last resort (verify with manufacturer-guided diagnostics).

Likely causes

Chafed wiring contacting a fused +12V feed near HVAC harness
Connector terminal pushed into contact with +12V source or corrosion bridging contacts
Internal short inside the right intake potentiometer/servo unit