B318A GMC Code - Left Rear Window Switch
Quick Answer
The driver and passenger window motors supply 12 V signal circuits to their respective window switches, when a window switch has been activated, a switch closes providing a ground to the appropriate signal circuit causing the voltage to drop to 0 V. Common causes include Faulty Left Rear Window Switch, Left Rear Window Switch harness is open or shorted, Left Rear Window Switch circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- B318A GMC indicates Left Rear Window Switch.
- Common causes
- Common causes include Faulty Left Rear Window Switch, Left Rear Window Switch harness is open or shorted, Left Rear Window Switch circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code B318A GMC Description
The driver window master control switch also contains control switches for the passenger, left rear and right rear window functions. When a window switch is pressed, a serial data message is sent to the Body Control Module (BCM). The BCM examines the request and checks for messages from other power window motors that may prohibit window movement. If no prohibitive messages have been received, the BCM will send a serial data message to the passenger window motor or to the appropriate rear window switch which will perform the command as requested.
What are the Possible Causes of the DTC B318A GMC?
- Faulty Left Rear Window Switch
- Left Rear Window Switch harness is open or shorted
- Left Rear Window Switch circuit poor electrical connection
- Faulty Body Control Module (BCM)
How to Fix the DTC B318A GMC?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the B318A GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Information for Specific GMC Models
- B318A 2014 GMC Sierra — Left Rear Window Switch
- B318A 2015 GMC Sierra — Left Rear Window Switch
- B318A 2016 GMC Sierra — Left Rear Window Switch
- B318A 2017 GMC Sierra — Left Rear Window Switch
- B318A 2018 GMC Sierra — Left Rear Window Switch
Frequently Asked Questions about B318A GMC Code
1. What are common symptoms of OBDII code B318A GMC related to the Left Rear Window Switch?
The common symptoms include the left rear window not responding to switch commands, being stuck in one position, or moving intermittently.
2. What could cause OBDII code B318A GMC for the Left Rear Window Switch?
Possible causes may include a faulty window switch, wiring issues, a defective window motor, or a problem with the window regulator.
3. How can I diagnose the OBDII code B318A GMC for the Left Rear Window Switch?
Diagnosis typically involves checking the wiring connections, testing the switch for continuity, inspecting the window motor, and ensuring proper power supply to the window system.
4. What is the typical repair for OBDII code B318A GMC for the Left Rear Window Switch?
The repair may involve replacing the faulty window switch, repairing damaged wiring, replacing the window motor or regulator, or addressing any underlying electrical issues.
5. Are there any DIY tips for addressing OBDII code B318A GMC related to the Left Rear Window Switch?
DIY enthusiasts can start by checking the fuse related to the window system, inspecting the switch for visible damage, and testing the window motor for proper functionality before seeking professional assistance.
6. Can OBDII code B318A GMC for the Left Rear Window Switch be intermittent?
Yes, the issue may sometimes be intermittent, which could be caused by loose connections, wiring issues, or a failing component that only malfunctions under certain conditions.
7. Is it safe to continue driving with OBDII code B318A GMC affecting the Left Rear Window Switch?
While driving with a malfunctioning left rear window may not pose immediate safety risks, it is advisable to address the issue promptly to maintain the full functionality and safety of your vehicle.
8. How much does it typically cost to repair OBDII code B318A GMC for the Left Rear Window Switch?
The cost of repair can vary depending on the specific cause of the issue, the extent of the damage, and whether you choose to address it yourself or seek professional help. Costs can range from a few dollars for a simple fix to a few hundred dollars for more complex repairs.
9. Can weather conditions affect OBDII code B318A GMC for the Left Rear Window Switch?
Extreme weather conditions or exposure to moisture can potentially exacerbate issues with the left rear window switch, making it more prone to malfunction. It's important to keep the window system protected from such elements.
10. Can resetting the vehicle's computer system resolve OBDII code B318A GMC for the Left Rear Window Switch?
Resetting the computer system may temporarily clear the error code, but if the underlying issue causing the code is not addressed, it is likely to return. It's best to diagnose and repair the root cause of the problem for a lasting solution.
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