OBD Guide
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B2109

Heated Wind Shield Relay Short To Battery

B2109 is an OBD-II diagnostic trouble code meaning: Heated Wind Shield Relay Short To Battery. Common causes: damaged relay harness, short circuit in wiring. Estimated repair cost: $22–89.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$22–89 (est.)

Symptoms

  • Heated windshield does not work
  • Constantly lit heating indicator
  • Battery discharge when the car is parked
  • Error message on display

Causes

  • Damaged relay harness
  • Short circuit in wiring
  • Faulty glass heating relay
  • Body Control Module (BCM) Problems
  • Corrosion of contacts in connectors

How to Fix

  1. Visual inspection of the wiring and connectors of the heating relay
  2. Checking resistance and voltage in the control circuit
  3. Diagnostics of relay operation with a multimeter
  4. Replacing a faulty relay if necessary
  5. Repair or replacement of damaged wires
  6. Resetting the fault code and checking system operation

Related codes

B2110B2111B2108

FAQ

What does the B2109 code mean?

B2109 is an OBD-II diagnostic trouble code that indicates: Heated Wind Shield Relay Short To Battery

What causes a B2109 error code?

The most common causes of B2109 include: Damaged relay harness; Short circuit in wiring; Faulty glass heating relay; Body Control Module (BCM) Problems.

How do I fix a B2109 diagnostic trouble code?

To fix B2109: Visual inspection of the wiring and connectors of the heating relay. Checking resistance and voltage in the control circuit. Diagnostics of relay operation with a multimeter. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B2109?

Limited driving only, diagnose soon

How much does it cost to fix B2109?

The estimated repair cost for B2109 is $22–89. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat