What Does B1437 Mean?
This code indicates the Body Control Module (BCM) has detected a short to ground in the wiper high/low speed relay coil control circuit. The BCM energizes the relay coil to switch between high and low wiper speeds, but the control circuit is reading lower resistance than expected, indicating current is flowing directly to ground instead of through the relay coil. This prevents proper wiper speed control and may blow fuses or damage the BCM output driver.
Common Causes
40%
Damaged or chafed wiring harness between BCM and wiper relay causing bare wire contact with chassis ground
30%
Failed wiper hi/low speed relay with internal short to ground in coil windings
20%
Corroded or damaged relay socket/connector causing pin-to-ground short
10%
Failed BCM output driver internally shorted, misdiagnosing normal circuit as grounded
Diagnostic Steps
1
Step 1: Perform visual inspection of wiper relay location, harness routing, and connectors for obvious damage, corrosion, or chafing against metal chassis components. Check for moisture intrusion in relay socket.
2
Step 2: Remove the wiper hi/low speed relay and inspect socket terminals for corrosion, pushed-back pins, or foreign debris. Using a digital multimeter, measure resistance from the relay coil control pin in the socket (BCM output side) to ground with ignition off - should read open circuit (OL) or very high resistance (>10K ohms).
3
Step 3: If socket shows proper resistance, test the removed relay coil for internal short by measuring resistance across coil terminals - should read 70-120 ohms typically, not near 0 ohms. Also check for continuity between coil terminals and relay case (should be open circuit).
4
Step 4: If socket reads low resistance to ground, disconnect BCM connector and re-measure from relay socket control pin to ground. If resistance becomes normal (open), BCM has failed internal short. If still shorted, trace and repair wiring harness between BCM and relay socket for short to ground.
5
Step 5: After repairs, reinstall relay, clear codes, and cycle wiper switch through all speeds while monitoring for code return. Verify proper high/low speed operation and check for blown fuses in wiper circuit.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected a short to ground in the wiper high/low speed relay coil control circuit. The BCM energizes the relay coil to switch between high and low wiper speeds, but the control circuit is reading lower resistance than expected, indicating current...
The most common cause of B1437 (Wiper Hi/Low Speed Relay Coil Circuit Short To Ground) is: Damaged or chafed wiring harness between BCM and wiper relay causing bare wire contact with chassis ground
Typical repair costs for B1437 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to drive in clear weather conditions, but wiper speed control may be inoperative or stuck in one speed, creating hazardous visibility during rain or snow. Repair before driving in inclement weather conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1437 to identify the root cause.
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Quick Info
Category
Body
System
Wiper/Washer System
Difficulty
Type
Manufacturer
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