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AutoCodes – GMC – B3873 GMC

B3873 GMC Code - Front Washer Relay Circuit

Quick Answer

The windshield washer function is controlled by the Body Control Module (BCM). Common causes include Faulty Front Washer Relay, Front Washer Relay harness is open or shorted, Front Washer Relay circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
B3873 GMC indicates Front Washer Relay Circuit.
Common causes
Common causes include Faulty Front Washer Relay, Front Washer Relay harness is open or shorted, Front Washer Relay circuit poor electrical connection.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
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Code Popularity 1,123
How popular is this code, among other codes? Low
What is this?
Table of contents Created and updated by William Orellana on Jun 14, 2023
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Code B3873 GMC Description

The windshield washer function is controlled by the Body Control Module (BCM). When the washer switch is pressed, low reference is applied through the switch contacts and the signal circuit to the body control module indicating the wash request. The body control module then applies voltage through the control circuit to the coil side of the windshield washer pump relay energizing the relay. With the relay energized, battery voltage from the fuse is applied through the switch contacts of the relay and the control circuit to the windshield washer fluid pump.
OBDII Code B3873 GMC - Front Washer Relay Circuit - AutoCodes.com
B3873 GMC Code - Front Washer Relay Circuit
What does this mean?

What are the Possible Causes of the DTC B3873 GMC?

  • Faulty Front Washer Relay
  • Front Washer Relay harness is open or shorted
  • Front Washer Relay circuit poor electrical connection
  • Faulty Body Control Module (BCM)

How to Fix the DTC B3873 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

B3873:01 Front Washer Relay Circuit Short to Battery
B3873:02 Front Washer Relay Circuit Short to Ground
B3873:04 Front Washer Relay Circuit Open

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B3873 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B3873 GMC code?

Need more information on how to fix the B3873 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B3873 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B3873 GMC Code

1. What does the OBDII code B3873 mean on a GMC vehicle?

B3873 indicates a malfunction in the Front Washer Relay Circuit, which controls the operation of the front windshield washer system.

2. What are the common symptoms of the B3873 code?

Symptoms include the windshield washer not spraying fluid, intermittent washer operation, or the washer relay making unusual noises.

3. What causes the B3873 code to appear?

Common causes include a faulty washer relay, damaged wiring or connectors in the washer circuit, a blown fuse, or a malfunctioning washer pump.

4. Can I still drive my GMC with the B3873 code active?

Yes, the vehicle is still drivable, but the windshield washer system may not function, potentially reducing visibility in poor weather conditions.

5. How do I diagnose the B3873 code?

Start by checking the washer relay and fuse. Inspect the wiring and connectors for damage or corrosion. If no issues are found, test the washer pump for proper operation.

6. How do I fix the B3873 code on my GMC?

Repairs may involve replacing the faulty washer relay, repairing damaged wiring or connectors, replacing a blown fuse, or replacing the washer pump if it's defective.

7. How much does it cost to fix the B3873 code?

Costs can vary, but replacing a washer relay typically costs $20-$50 for the part, plus labor if done by a mechanic. Wiring repairs or pump replacement may cost more, depending on the extent of the issue.

8. Can I clear the B3873 code without fixing it?

Clearing the code with an OBDII scanner will temporarily remove it, but the underlying issue will cause the code to reappear until properly fixed.

9. What tools are needed to troubleshoot the B3873 code?

You'll need an OBDII scanner, a multimeter to test electrical components, and basic hand tools to access and inspect the washer system components.

10. Is the B3873 code common on GMC vehicles?

This code is not particularly common but may occur in older vehicles or those with frequent use of the washer system in harsh weather conditions.

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