Wiper Low Speed Relay Circuit
Table of contents
B3874 GMC Possible Causes
- Faulty Wiper Low Speed Relay
- Wiper Low Speed Relay harness is open or shorted
- Wiper Low Speed Relay circuit poor electrical connection
- Faulty Body Control Module (BCM)
How do I fix code B3874 GMC?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Cost of diagnosing the B3874 GMC code
The cost of diagnosing the B3874 GMC code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
B3874 GMC Description
The Body Control Module (BCM) controls and monitors the state of the wiper control circuit. When the windshield wiper switch is placed in to a low speed setting, a signal is applied to the BCM. The BCM then applies the battery positive voltage to the coil side of the relay through the relay control circuit. The Diagnostic Trouble Code (DTC) sets when the ignition is in the ON position or the ignition voltage is between 9-16 volts.