Left Headlight High Beam Circuit Malfunction
The B0048 code means the vehicle's onboard diagnostic system has detected: Left Headlight High Beam Circuit Malfunction. This is a moderate severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- easy
- Estimated cost
- $10 - $350 (parts and labor)
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Common Symptoms
- Left high beam does not illuminate
- High beam indicator on dash does not light up on left
- Reduced visibility on dark roads with high beams
- Only right high beam works when activated
- Flash-to-pass feature not working on left side
Probable Causes (Ranked by Likelihood)
- Burned out left high beam bulb or filament Very High
- Corroded high beam connector or socket High
- Faulty multifunction switch (dimmer) Moderate
- Open circuit in left high beam wiring Low
Step-by-Step Diagnostic Procedure
-
Inspect left high beam bulb or filament
-
Check connector at headlight for corrosion
-
Test voltage at high beam terminal with high beams on
-
Test multifunction switch for high beam output signal
-
Check wiring from switch to left headlight assembly
Frequently Asked Questions
Is the high beam a separate bulb from the low beam?
It depends on the vehicle. Some use a dual-filament bulb like the H13 or 9007 where one bulb has both filaments. Others use separate bulbs for high and low beams.
Can I still use my low beams if the high beam is out?
Yes. High and low beams operate on separate circuits or filaments. A failed high beam does not affect low beam operation.
What is flash-to-pass?
Flash-to-pass is a feature that briefly activates the high beams when you pull the turn signal stalk toward you. If the high beam bulb is burned out on one side, this feature will be affected.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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