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Home / DTC / B2805 — Steering Whl Controls HVAC Switch Circuit Malfunction

B2805 — Steering Whl Controls HVAC Switch Circuit Malfunction

Detailed page for trouble code B2805.

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Code

B2805

HUMMER B — Body

Steering Whl Controls HVAC Switch Circuit Malfunction

Brand: HUMMER
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged or corroded connector at steering column or HVAC switch
  • Broken wiring or chafed harness in steering column or between steering column and BCM/HVAC module
  • Faulty steering‑wheel HVAC switch assembly
  • Defective clock spring (spiral cable) or poor contact in clock spring
  • Blown fuse or poor ground in related circuit
  • Loss of network communication (LIN/CAN) to HVAC or BCM

Symptoms

  • Steering‑wheel HVAC controls non‑responsive or erratic
  • HVAC control functions only from dash controls
  • Steering wheel audio/phone controls may also be intermittent if shared wiring
  • DTC stored and possible warning message on cluster
  • Intermittent loss of HVAC requests from steering wheel

What to check

  • Read DTCs with a scan tool; record freeze frame and related codes
  • Verify battery voltage and charge; check related fuses and grounds
  • Visually inspect steering column harness, connectors, and clock spring for damage
  • Operate steering wheel switches while monitoring signal with scan tool or scope
  • Check for lost communication DTCs (CAN/LIN) that could affect the circuit
  • Verify connectors at BCM/HVAC module are fully seated and pins not corroded

Signal parameters

  • Reference supply: typically 5 V reference to the steering wheel switch circuit (verify with wiring diagram)
  • Switch output: voltage change or LIN message when HVAC buttons pressed (0–5 V or digital LIN frame depending on design)
  • Continuity through clock spring: near 0 ohms for switch circuits; infinite if open
  • Short to voltage: near battery voltage when shorted; short to ground: near 0 V
  • Network: LIN/CAN messages present and valid on bus when pressing steering wheel buttons (use scan tool/oscilloscope)

Diagnostic algorithm

  1. Retrieve all stored codes and freeze frame; note any related network/comms codes (U-codes).
  2. Verify vehicle battery voltage >=12.4 V and check fuses/relays for steering wheel and HVAC circuits.
  3. Visually inspect steering column harness, connectors and clock spring for damage, pin corrosion, or loose terminals.
  4. With ignition ON, monitor the steering wheel HVAC switch inputs with a scan tool or backprobe connector to observe expected voltage or LIN messages while pressing buttons.
  5. If signals are absent or intermittent, check continuity of the wiring from the steering wheel connector through the clock spring to the BCM/HVAC connector. Measure resistance with wheel centered; rotate the wheel while rechecking for opens/intermittents.
  6. Check for shorts to ground or battery on the switch circuit wires using an ohmmeter and by disconnecting connectors to isolate sections.
  7. If wiring and clock spring are good, swap or bench‑test the steering wheel HVAC switch assembly if possible, or verify correct LIN/CAN communication to the HVAC module with a serial data tool.
  8. If communication messages are present but the module does not respond, perform BCM/HVAC module hardware tests and software checks (reflash/updates) per manufacturer procedures.
  9. Replace failed component (clock spring, switch, or wiring repair) and clear codes. Verify operation and road/test to ensure DTC does not return.
  10. Safety note: Follow airbag safety procedures (disconnect battery, wait proper time) before removing the steering wheel or clock spring.

Likely causes

  • Wiring harness damage / intermittent open at steering column
  • Failed clock spring causing loss of continuity
  • Failed steering‑wheel HVAC switch assembly
  • Connector corrosion or poor pin contact at steering column or BCM

Fault status

⚠️ Status
Steering wheel HVAC switch circuit malfunction detected — check wiring, clock spring, and module communication.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

B2804 B2806 U0073 U0100 U0140
Repair manuals

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138

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Code

B2805

HYUNDAI B — Body

No Response NM Message (TMU/T-BOX/CUbiS)

Brand: HYUNDAI
Type: B — Body
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Damaged or corroded connector at steering column or HVAC switch
  • Broken wiring or chafed harness in steering column or between steering column and BCM/HVAC module
  • Faulty steering‑wheel HVAC switch assembly
  • Defective clock spring (spiral cable) or poor contact in clock spring
  • Blown fuse or poor ground in related circuit
  • Loss of network communication (LIN/CAN) to HVAC or BCM

Symptoms

  • Steering‑wheel HVAC controls non‑responsive or erratic
  • HVAC control functions only from dash controls
  • Steering wheel audio/phone controls may also be intermittent if shared wiring
  • DTC stored and possible warning message on cluster
  • Intermittent loss of HVAC requests from steering wheel

What to check

  • Read DTCs with a scan tool; record freeze frame and related codes
  • Verify battery voltage and charge; check related fuses and grounds
  • Visually inspect steering column harness, connectors, and clock spring for damage
  • Operate steering wheel switches while monitoring signal with scan tool or scope
  • Check for lost communication DTCs (CAN/LIN) that could affect the circuit
  • Verify connectors at BCM/HVAC module are fully seated and pins not corroded

Signal parameters

  • Reference supply: typically 5 V reference to the steering wheel switch circuit (verify with wiring diagram)
  • Switch output: voltage change or LIN message when HVAC buttons pressed (0–5 V or digital LIN frame depending on design)
  • Continuity through clock spring: near 0 ohms for switch circuits; infinite if open
  • Short to voltage: near battery voltage when shorted; short to ground: near 0 V
  • Network: LIN/CAN messages present and valid on bus when pressing steering wheel buttons (use scan tool/oscilloscope)

Diagnostic algorithm

  1. Retrieve all stored codes and freeze frame; note any related network/comms codes (U-codes).
  2. Verify vehicle battery voltage >=12.4 V and check fuses/relays for steering wheel and HVAC circuits.
  3. Visually inspect steering column harness, connectors and clock spring for damage, pin corrosion, or loose terminals.
  4. With ignition ON, monitor the steering wheel HVAC switch inputs with a scan tool or backprobe connector to observe expected voltage or LIN messages while pressing buttons.
  5. If signals are absent or intermittent, check continuity of the wiring from the steering wheel connector through the clock spring to the BCM/HVAC connector. Measure resistance with wheel centered; rotate the wheel while rechecking for opens/intermittents.
  6. Check for shorts to ground or battery on the switch circuit wires using an ohmmeter and by disconnecting connectors to isolate sections.
  7. If wiring and clock spring are good, swap or bench‑test the steering wheel HVAC switch assembly if possible, or verify correct LIN/CAN communication to the HVAC module with a serial data tool.
  8. If communication messages are present but the module does not respond, perform BCM/HVAC module hardware tests and software checks (reflash/updates) per manufacturer procedures.
  9. Replace failed component (clock spring, switch, or wiring repair) and clear codes. Verify operation and road/test to ensure DTC does not return.
  10. Safety note: Follow airbag safety procedures (disconnect battery, wait proper time) before removing the steering wheel or clock spring.

Likely causes

  • Wiring harness damage / intermittent open at steering column
  • Failed clock spring causing loss of continuity
  • Failed steering‑wheel HVAC switch assembly
  • Connector corrosion or poor pin contact at steering column or BCM

Fault status

⚠️ Status
Steering wheel HVAC switch circuit malfunction detected — check wiring, clock spring, and module communication.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

B2804 B2806 U0073 U0100 U0140
371

Browse 371 HYUNDAI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

HYUNDAI

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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

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