B3718 on 2004-2011 Chevrolet Colorado: Wiper Parking Fault Causes and Fixes

What's Unique About the 2004-2011 Chevrolet COLORADO

This is a well-documented issue on the first-generation Chevrolet Colorado and its platform mates, the GMC Canyon, Hummer H3, and Isuzu i-Series. General Motors released a specific Technical Service Bulletin (TSB #PIT3827D) for this exact problem, which points to common failure points in either the wiper motor's internal park switch or the wiring harness. Unlike a generic wiper failure, this code on this truck platform is very often tied to one of these two specific, known issues.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• Windshield wipers do not stop in the correct 'park' position at the bottom of the windshield.
• Wipers cycle one to three times after being turned off before stopping.
• Wipers stop at a random position on the windshield.
• Wipers may activate on their own when the ignition is turned on, even if the switch is off.
• Only the high-speed wiper setting works correctly, while intermittent and low speeds fail.

Most Likely Causes

1. Faulty Wiper Motor Park Switch 🔴 High Probability The internal park switch, which signals the wiper's home position to the BCM by providing a ground signal, is a common failure point. Over time, the contacts within the switch wear out or fail, leading to an incorrect or missing position signal.
   How to confirm: After confirming the wiring is intact via a continuity test or jumper wire, the wiper motor is the confirmed point of failure. 🎬 Watch: A mechanic's guide to diagnosing a faulty wiper motor. If a scan tool is available, monitor the 'Wiper Park Switch' parameter; if it does not change to 'Active' when the wipers are near the park position, the switch is bad. Since the switch is internal, this confirms the need for motor replacement.
   Typical fix: Replace the entire windshield wiper motor assembly. The park switch is integrated into the motor and is not typically sold as a separate component.
   Est. part cost: $65-$245
2. Open or Damaged Wiring (Circuit 196) 🟡 Medium Probability GM Technical Service Bulletin PIT3827D specifically identifies an open in circuit 196 (a yellow wire) as a primary cause. The TSB highlights two common chafe/break points for this wire: in the harness under the electronic brake control module (EBCM) in the engine bay, and in the harness behind the instrument panel (IP), approximately 8-12 inches from the BCM connector. Rodent damage has also been reported by owners in this area.
   How to confirm: Perform a continuity test on the yellow wire (circuit 196) between the BCM connector and the wiper motor connector. A lack of continuity confirms a break in the wire. The TSB also recommends using a fused jumper wire to temporarily bypass circuit 196 as a test; if the wipers park correctly with the jumper in place, the original wire is confirmed to be open.
   Typical fix: Locate the break in the wire and repair it using proper soldering and heat-shrink techniques or by replacing the damaged section of the harness.
   Est. part cost: $1-$20

Rare But Worth Checking

• Faulty Body Control Module (BCM): The BCM is the computer that controls the wipers. While it can fail, it is far less common than the motor or wiring. This should only be considered after definitively ruling out the other, more common causes with wiring tests and/or motor replacement.

Diagnosis Steps

1. Confirm the symptoms by turning the wipers on and then off. Note if they fail to park correctly or cycle after being shut off.
2. Use an OBD-II scanner capable of reading body codes to confirm that B3718 is stored in the Body Control Module (BCM).
3. Visually inspect the wiring harness leading to the wiper motor for any obvious signs of chafing, melting, or corrosion, paying close attention to the area under the EBCM.
4. As recommended by TSB PIT3827D, test the integrity of circuit 196 (yellow wire). You can do this either by performing a continuity test between the BCM and wiper motor connectors or by using a fused jumper wire to bypass the factory wire. If the jumper wire fixes the issue, the original wire is broken.
5. If using a scan tool, monitor the 'Wiper Park Switch' data PID. It should read 'Active' when the wipers are parked and 'Inactive' when they are moving. If it's stuck on 'Inactive', the problem is either the wiring or the park switch itself.
6. If the wiring continuity test passes (or the jumper wire does not fix the problem), the fault is internal to the wiper motor assembly.
7. Replace the windshield wiper motor assembly. This involves removing the wiper arms and the plastic cowl cover to access the motor and linkage.
🎬 Watch: Step-by-step wiper motor and cowl replacement walkthrough.

Parts You'll Likely Need

• Windshield Wiper Motor Assembly (OEM #88958223, 25809218) — This is the most common cause of code B3718 if wiring is confirmed to be good. The internal park switch fails and is not serviced separately, requiring replacement of the entire motor.
  Trusted brands: ACDelco, Cardone, WAI Global, Dorman
  OEM price range: $240-$415
  Aftermarket price range: $65-$190

Related Codes That Often Appear With This One

• B3715 — This code is also related to the wiper park circuit and is frequently mentioned alongside B3718 in the official GM Technical Service Bulletin PIT3827D.

Technical Service Bulletins (TSBs) & Recalls

• PIT3827D: Addresses wipers cycling one to three times before stopping incorrectly, pointing to an open in circuit 196 (yellow wire) or a faulty wiper motor. Specifies two common break locations: under the EBCM and near the BCM connector.

Platform-Specific Known Issues

• GM issued Technical Service Bulletin #PIT3827D, which covers this exact issue on 2004-2012 Colorado and Canyon models. It details the symptoms of wipers cycling multiple times before stopping incorrectly and points technicians to inspect circuit 196 (yellow wire) for an open or to replace the wiper motor. The TSB specifically calls out two likely locations for the wire break: under the EBCM and 8-12 inches from the BCM connector.
• Real-World Repair: The Broken Yellow Wire: An owner on the 'BAT Auto Technical' forum documented their experience with code B3718 and the associated symptoms. After initially replacing the wiper motor and relays with no change, they followed the advice in TSB PIT3827. Upon inspecting the yellow wire (circuit 196), they discovered it had been completely severed, likely by a rodent. Repairing the wire solved the problem entirely, highlighting the importance of checking the wiring before replacing expensive components.

Mechanic-Grade Diagnostic Values

• Wiper Park Switch Signal Voltage (Circuit 196) — expected: Near 0V (ground) when wipers are in the parked position. Should read >1V (open/high) when wipers are moving.. Failure: The BCM sets code B3718 when it sees a high voltage (>1V) on this circuit for more than one second when it expects to see a ground signal (wipers are off and should be parked).

Scan Tool Commands That Help

• GM Tech2 or equivalent professional scanner: Live Data > BCM > Wiper Park Switch — Use this to monitor the status of the park switch signal as seen by the BCM. The status should change from 'Inactive' to 'Active' as the wipers reach the park position. If the status is stuck on 'Inactive' even when the wipers are parked, it confirms the signal is not reaching the BCM, pointing to either a wiring or motor park switch fault.
• GM Tech2 or equivalent professional scanner: Special Functions > BCM > Wiper Relay Control — This bidirectional control allows a technician to command the wiper relays (Low, High) directly from the scan tool. This helps verify that the BCM, relays, and motor are capable of functioning, isolating the problem to the park logic or multifunction switch input.

Wiring & Ground Locations

• Circuit 196 (Yellow Wire) - BCM Side — At the Body Control Module (BCM) located behind the right kick panel. The wire is in connector C2 (often blue or grey) at pin position A3.. This is the primary point for testing the park switch signal at the control module. A continuity test should be performed from this pin to the corresponding pin at the wiper motor.
• Circuit 196 (Yellow Wire) - Motor Side — At the windshield wiper motor electrical connector, located in the left rear of the engine compartment. The wire is at pin position A.. This is the other end of the critical park signal circuit. Testing here confirms if the signal is being sent from the motor and helps isolate a wire break between this point and the BCM.
• G105 — Located in the left front of the engine compartment, often near the underhood fuse block or EBCM.. This is a primary ground point for the wiper motor and wiper relays. Corrosion or a loose connection at G105 can cause erratic wiper operation and various electrical faults, even if the park circuit itself is intact.
• G103 — Located at the left rear of the engine compartment on the cowl, often above the brake booster.. This is a major ground point for the BCM and the multifunction switch. A fault at this ground can cause numerous BCM-related issues, including incorrect interpretation of switch signals or erratic behavior.

Real Owner Repair Stories

• 355nation.net forum user (2004 Chevrolet Colorado) — Wipers would not park correctly and would stop mid-windshield, setting code B3718.
  ❌ Tried (didn't work) Replacing the wiper motor, Replacing the wiper relays
  ✅ What actually fixed it The user performed a continuity test on the yellow wire (Circuit 196) from BCM connector C2, pin A3, to the wiper motor connector, pin A, and found it was open (broken). The break was located in the wiring harness near the firewall/brake booster area. Repairing the broken section of the yellow wire resolved all symptoms and cleared the code.

OEM Part Supersession History

• 88958223 → 25809218, then 25999027 — Standard part evolution, design updates, or change in manufacturer.
  Heads up: The newer part numbers are generally backward compatible for the specified model years, but always verify fitment with the VIN before purchasing.

Model Year Variations Within This Range

• 2004-2012: The core issue and diagnostic procedure for B3718 remain consistent across the entire first generation. However, the BCM itself may have different part numbers and minor compatibility differences based on year and vehicle options (RPO codes). A replacement BCM must be programmed to the vehicle's VIN and options.