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πŸ’‘Headlight Bulb Size

Mercury Mountaineer Headlight Bulb Size

Find the correct headlight bulb size for your Mercury Mountaineer. Covers low beam, high beam, fog lights, and turn signals for all years.

Quick Answer

The Mercury Mountaineer headlight bulb size depends on the model year and trim. Common sizes include H11 (low beam), 9005/HB3 (high beam), and H16 (fog lights) β€” see the full breakdown below.

2005-2010

2005-2010
Low BeamH11 or H7
High Beam9005/HB3
Fog LightsH16, H11, or 9006 (if equipped)
Turn Signal (Front)7440/T20 or 3157 amber
Headlight TypeHalogen projector or reflector
Notes
  • β†’Never touch halogen bulbs with bare fingers β€” skin oil causes hot spots and premature failure
  • β†’LED upgrade bulbs are available but may cause CANBUS errors on some models
  • β†’Replace bulbs in pairs β€” if one side burned out, the other is likely near end of life

1999-2004

1999-2004
Low Beam9006/HB4 or H4
High Beam9005/HB3 or H4
Fog Lights9006 or 880/881 (if equipped)
Turn Signal (Front)3157 amber
Headlight TypeHalogen reflector
Notes
  • β†’Never touch halogen bulbs with bare fingers β€” skin oil causes hot spots and premature failure
  • β†’Replace bulbs in pairs β€” if one side burned out, the other is likely near end of life

1997-1998

1997-1998
Low Beam9006/HB4 or H4
High Beam9005/HB3 or H4
Fog Lights9006 or 880/881 (if equipped)
Turn Signal (Front)3157 amber
Headlight TypeHalogen reflector
Notes
  • β†’Never touch halogen bulbs with bare fingers β€” skin oil causes hot spots and premature failure
  • β†’Replace bulbs in pairs β€” if one side burned out, the other is likely near end of life

Frequently Asked Questions

What size headlight bulb does a Mercury Mountaineer use?
The Mercury Mountaineer headlight bulb size varies by year. Newer models often use factory LED units, while older models use H11, H7, or 9006 halogen bulbs. Check the year-specific specs below for your exact fitment.
Can I put LED bulbs in my Mercury Mountaineer?
If your Mercury Mountaineer has halogen headlights, you can install LED replacement bulbs. Look for bulbs with a proper beam pattern (projector-compatible) to avoid blinding other drivers. Some models may need anti-flicker adapters.
How do I replace the headlight bulb on a Mercury Mountaineer?
On most Mercury Mountaineer models, you can access the headlight bulb from behind the headlight assembly in the engine bay. Twist the bulb socket counterclockwise, pull out the old bulb, insert the new one (don't touch the glass), and twist back in.
Why does my Mercury Mountaineer headlight keep burning out?
Frequent bulb burnout on the Mercury Mountaineer is usually caused by a loose connection, moisture in the housing, touching the bulb glass during installation, or a voltage regulator issue. Check the connector and housing seal.

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