Left Rear Side Marker Light Circuit Open
The B0064 code means the vehicle's onboard diagnostic system has detected: Left Rear Side Marker Light Circuit Open. This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- easy
- Estimated cost
- $5 - $120 (parts and labor)

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Common Symptoms
- Left rear side marker not illuminating
- Bulb check warning on cluster
- Reduced rear side visibility at night
- Failed vehicle safety inspection
Probable Causes (Ranked by Likelihood)
- Burned out rear side marker bulb Very High
- Corroded rear marker socket High
- Water intrusion in rear marker housing Moderate
- Damaged wiring in rear quarter panel Low
Step-by-Step Diagnostic Procedure
-
Inspect left rear side marker bulb
-
Check socket for corrosion and ground
-
Test voltage with parking lights on
-
Inspect wiring through rear quarter panel
Frequently Asked Questions
Where is the rear side marker?
On the rear bumper side or rear quarter panel near the tail light assembly.
Can I use LED replacement bulbs?
Yes, but some vehicles may require a load resistor to prevent hyperflash.
Does this affect brake lights?
No, the rear side marker operates on a separate circuit.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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