What Does B1245 Mean?
This code indicates the Body Control Module (BCM) has detected an unwanted voltage present on the rear wiper motor run relay control circuit when it should be off. The BCM monitors the relay control circuit and has identified that battery voltage is continuously present, suggesting the circuit is shorted to a power source. This condition can cause the rear wiper motor to run continuously or fail to operate correctly, and may drain the battery if left unaddressed.
Common Causes
40%
Damaged or chafed wiring harness causing direct short to battery voltage in rear wiper relay control circuit
30%
Failed rear wiper motor run relay with internal short to power or stuck closed contacts
20%
Faulty Body Control Module with internal short on relay driver circuit
10%
Corroded or damaged connector terminals at relay socket creating cross-circuit short to power
Diagnostic Steps
1
Step 1: Perform visual inspection of rear wiper relay, relay socket, and all associated wiring from BCM to relay and motor. Look for melted relay housing, burnt pins, chafed wires near liftgate hinges, or evidence of water intrusion.
2
Step 2: Remove the rear wiper motor run relay and use a digital multimeter to measure voltage on the relay control terminal at the socket with ignition on. Reading should be 0-1 volts when system is commanded off; battery voltage confirms short to power in wiring or BCM.
3
Step 3: If battery voltage is present at relay socket control terminal, disconnect the BCM connector and retest. If voltage disappears, BCM has internal fault; if voltage remains, trace and inspect wiring between relay and BCM for shorts to power sources, particularly in liftgate flex area.
4
Step 4: If no voltage found at relay socket, test the suspect relay with an ohmmeter to verify contacts are not shorted closed and test relay operation with external 12V power supply. Replace if contacts remain closed or show continuity when de-energized.
5
Step 5: After repairs, clear codes, command rear wiper operation using scan tool bidirectional controls, then turn off and verify BCM no longer detects voltage on control circuit. Cycle rear wiper multiple times and verify code does not return.
Estimated Repair Cost
$100 - $650
Parts + labor, varies by vehicle and location
This code indicates the Body Control Module (BCM) has detected an unwanted voltage present on the rear wiper motor run relay control circuit when it should be off. The BCM monitors the relay control circuit and has identified that battery voltage is continuously present, suggesting the circuit is sh...
The most common cause of B1245 (Wiper Rear Motor Run Relay Circuit Short to Battery) is: Damaged or chafed wiring harness causing direct short to battery voltage in rear wiper relay control circuit
Typical repair costs for B1245 range from $100 to $650, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Safe to continue driving as this only affects rear window visibility cleaning function. However, the short circuit may cause battery drain if relay remains energized continuously, and should be repaired within a reasonable timeframe to prevent being stranded.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1245 to identify the root cause.
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Quick Info
Category
Body
System
Body Control System (Rear Wiper)
Difficulty
Type
Manufacturer
Recommended Tools
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