OBD Guide
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C1065

Brake Light Relay Circuit Failure

C1065 is an OBD-II diagnostic trouble code meaning: Brake Light Relay Circuit Failure. Common causes: faulty brake light relay, open or short circuit in the circuit. Estimated repair cost: $11–56.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$11–56 (est.)

Symptoms

  • Brake lights don't work
  • The malfunction indicator on the dashboard is on
  • Error C1065 is stored in the control unit memory

Causes

  • Faulty brake light relay
  • Open or short circuit in the circuit
  • Wiring Harness Problems
  • Oxidation of relay contacts
  • Control unit malfunction (rare)

How to Fix

  1. Check the brake light relay for malfunctions
  2. Inspect the wiring harness for damage
  3. Check continuity with a multimeter
  4. Replace the relay if it is faulty
  5. Repair open or short circuit
  6. Clean relay contacts from oxidation

Related codes

C1066B1342

FAQ

What does the C1065 code mean?

C1065 is an OBD-II diagnostic trouble code that indicates: Brake Light Relay Circuit Failure

What causes a C1065 error code?

The most common causes of C1065 include: Faulty brake light relay; Open or short circuit in the circuit; Wiring Harness Problems; Oxidation of relay contacts.

How do I fix a C1065 diagnostic trouble code?

To fix C1065: Check the brake light relay for malfunctions. Inspect the wiring harness for damage. Check continuity with a multimeter. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with C1065?

Do not drive — repair immediately

How much does it cost to fix C1065?

The estimated repair cost for C1065 is $11–56. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat