Windshield Wiper Power Circuit Short to Ground
The B1843 code indicates that the body control module (GEM/BCM) has detected a short to ground in the main power supply circuit for the front windshield wiper motor. The module monitors voltage and resistance in this circuit; if abnormal continuity to ground is identified during the ignition cycle or wiper operation, this manufacturer-specific DTC is set. This fault can cause the wipers to become completely inoperative, blow the protective fuse, or overheat the affected wiring. Diagnosis should focus on the wiring harness, wiper motor, control relays, and connections to prevent loss of visibility in adverse weather.
1. Commonly Affected Makes
2. Most Common Causes
- Wiper power supply wiring chafed, exposed, or shorted to chassis ground
- Front wiper motor internal failure (coil shorted to housing)
- Defective wiper control relay with welded or stuck contacts
- Corroded or moisture-damaged connector at the wiper motor or BCM, causing pin-to-pin short
- Internal BCM fault that incorrectly grounds the wiper power circuit
3. Symptoms You Will Notice
- Wipers do not operate at all
- Wiper fuse blows repeatedly
4. Step-by-Step Diagnosis
Check for blown wiper fuse and replace if necessary
Inspect wiper motor power supply wiring for chafing, burns, or shorts to ground
Test wiper motor for internal short by measuring resistance between power terminal and motor housing
Verify wiper relay operation and check for welded contacts
Inspect connectors at wiper motor and BCM for corrosion, moisture, or bent pins
If all else is normal, test BCM for internal short or replace with known-good module
5. Frequently Asked Questions
Is it safe to drive?▼
Driving without wipers is unsafe in rain or snow. The short could also blow a fuse or cause wiring damage. It's best to repair before driving in wet conditions.
How much does it cost to fix?▼
Repair costs range from $100 to $500 depending on the cause. Simple wiring repair may be $100-$200, while replacing the wiper motor or BCM can cost $300-$500.