OBD Guide
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B18B5

Master Switch Front Left Window Switch

B18B5 is an OBD-II diagnostic trouble code meaning: Master Switch Front Left Window Switch. Common causes: switch failure, open or shorted wiring harness. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$56–167 (est.)

Symptoms

  • Left front window doesn't work
  • The switch does not respond to pressing
  • Intermittent window operation

Causes

  • Switch failure
  • Open or shorted wiring harness
  • Problems with the control module

How to Fix

  1. Check the switch for physical damage
  2. Ring the switch circuit
  3. Check power and ground circuit
  4. If necessary, replace the switch or repair the wiring harness

Related codes

B18B6B18B7B18B8

FAQ

What does the B18B5 code mean?

B18B5 is an OBD-II diagnostic trouble code that indicates: Master Switch Front Left Window Switch

What causes a B18B5 error code?

The most common causes of B18B5 include: Switch failure; Open or shorted wiring harness; Problems with the control module.

How do I fix a B18B5 diagnostic trouble code?

To fix B18B5: Check the switch for physical damage. Ring the switch circuit. Check power and ground circuit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B18B5?

Do not drive — repair immediately

How much does it cost to fix B18B5?

The estimated repair cost for B18B5 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat