What Does B1843 Mean?
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected an abnormal short-to-ground condition in the front windshield wiper motor power supply circuit. The BCM monitors the wiper circuit and sets this code when it detects current flow to ground that exceeds normal parameters, suggesting damaged wiring, a faulty wiper motor, or a compromised relay/switch. This prevents proper wiper operation and may cause the wipers to be completely inoperative or the circuit protection to open.
Common Causes
40%
Damaged or chafed wiring harness between BCM and wiper motor, causing direct short to ground from pinch points near hood hinges or cowl area
30%
Failed front wiper motor with internal short to ground in motor windings or brushes
20%
Faulty wiper relay or wiper control module with internal short circuit creating ground path
10%
Corroded or water-damaged wiper motor connector creating unintended ground path
Diagnostic Steps
1
Step 1: Perform visual inspection of the wiper motor wiring harness from BCM to motor, checking for obvious chafing, pinch points, damaged insulation, or signs of water intrusion at connectors. Pay special attention to areas near hood hinges and cowl.
2
Step 2: Disconnect the wiper motor connector and measure resistance from the power supply wire (typically B+ feed from BCM) to chassis ground using a digital multimeter. Reading should be infinite ohms (open circuit); any continuity indicates a wiring harness short.
3
Step 3: If wiring shows no short, measure resistance across the wiper motor terminals with motor disconnected. Compare readings to manufacturer specifications (typically 2-5 ohms for low speed, higher for high speed). Zero ohms or direct continuity to motor housing indicates internal motor short.
4
Step 4: Inspect and test the wiper relay by removing it and checking for continuity between power output terminal and ground with relay de-energized (should be open). Check relay socket terminals for corrosion or bent pins creating shorts.
5
Step 5: If all components test good, perform voltage drop test on ground side of circuit while attempting wiper operation to identify high-resistance ground connections that may cause BCM to misinterpret as short condition.
6
Step 6: After repairs, clear codes, cycle wiper switch through all positions (off, intermittent, low, high) and verify proper operation. Re-scan for codes to confirm repair success.
Estimated Repair Cost
$100 - $450
Parts + labor, varies by vehicle and location
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected an abnormal short-to-ground condition in the front windshield wiper motor power supply circuit. The BCM monitors the wiper circuit and sets this code when it detects current flow to ground that exceeds normal para...
The most common cause of B1843 (Wiper Front Power Circuit Short To Ground) is: Damaged or chafed wiring harness between BCM and wiper motor, causing direct short to ground from pinch points near hood hinges or cowl area
Typical repair costs for B1843 range from $100 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is safe to drive in clear weather conditions, but inoperative wipers create a serious safety hazard in rain, snow, or reduced visibility situations. Repair should be completed before driving in inclement weather, and the short circuit could potentially drain the battery or cause further electrical damage if left unaddressed.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1843 to identify the root cause.
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Quick Info
Category
Body
System
Body Electrical System - Wiper/Washer
Difficulty
Type
Manufacturer
Recommended Tools
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