OBD Guide

B3874

Wiper Low Speed Relay Circuit

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$11–56 (est.)

Symptoms

  • Wipers do not work at low speed
  • Wipers only work at high speed
  • Intermittent wiper operation

Causes

  • Faulty low speed wiper relay
  • Open or short circuit in wiring harness
  • Problems with the control signal from the control unit
  • Oxidation of relay contacts or connectors

How to Fix

  1. Check the low speed wiper relay
  2. Inspect the wiring harness for damage
  3. Check relay contacts and connectors for oxidation
  4. Replace relay if necessary
  5. Check the control signal from the control unit

Related codes

Error B3874 by Vehicle Brand