What Does B1618 Mean?
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected a short to ground in the rear wiper disable switch circuit. The BCM monitors the electrical circuit of the switch that allows the driver to disable or enable the rear wiper function, and has identified that the circuit voltage is being pulled to ground when it should not be. This prevents the BCM from receiving proper switch input signals, potentially affecting rear wiper operation control.
Common Causes
45%
Damaged, chafed, or pinched wiring harness between the rear wiper disable switch and BCM causing direct short to vehicle ground
30%
Failed rear wiper disable switch with internal short to ground condition
15%
Corroded or moisture-damaged connector pins at the switch or BCM causing intermittent ground short
10%
Failed Body Control Module with internal circuit fault on the switch input channel
Diagnostic Steps
1
Step 1: Perform visual inspection of the rear wiper disable switch, its connector, and associated wiring harness from the switch back to the BCM. Look for damaged insulation, chafed wires, corrosion, moisture intrusion, or any signs of physical damage, particularly at pinch points near tailgate hinges or body panels.
2
Step 2: Disconnect the rear wiper disable switch connector and measure resistance between the switch signal circuit terminal (at the vehicle harness side) and chassis ground using a digital multimeter. Reading should show infinite resistance (open circuit). If continuity to ground is present, there is a wiring harness short.
3
Step 3: If harness tests good, measure resistance across the rear wiper disable switch terminals in both switch positions. Compare readings to manufacturer specifications (typically open/closed states). If switch shows continuity to ground when it should not, replace the switch.
4
Step 4: With switch disconnected, clear the DTC and monitor live data for the rear wiper disable switch input status. The BCM should show a high/open state. If it still shows a grounded condition with switch disconnected, suspect BCM internal fault.
5
Step 5: Repair or replace identified faulty components (wiring, switch, or BCM), reconnect all connections, clear DTCs, and perform operational test of rear wiper disable function through multiple cycles to verify proper operation and confirm no code returns.
Estimated Repair Cost
$75 - $450
Parts + labor, varies by vehicle and location
This diagnostic trouble code indicates that the Body Control Module (BCM) has detected a short to ground in the rear wiper disable switch circuit. The BCM monitors the electrical circuit of the switch that allows the driver to disable or enable the rear wiper function, and has identified that the ci...
The most common cause of B1618 (Wiper Rear Disable Switch Circuit Short To Ground) is: Damaged, chafed, or pinched wiring harness between the rear wiper disable switch and BCM causing direct short to vehicle ground
Typical repair costs for B1618 range from $75 to $450, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This code does not affect vehicle safety or driveability and it is safe to continue driving. The rear wiper disable function may be inoperative, which could affect rear visibility in inclement weather, but the issue is non-critical and can be addressed at your convenience.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1618 to identify the root cause.
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Quick Info
Category
Body
System
Body Control and Wiper System
Difficulty
Type
Manufacturer
Recommended Tools
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