Maybe you forgot the high brake light? that is part of the tail/parking lights too?

The others are right a corroded bulb/socket can add resistance and mess up the works. Clean the bulb and socket with dry scotch brite and use a little di-electric silicone to prevent corrosion.

If it comes on with parking lights, look there first.

Sometimes you may find that bulbs need to be replaced in pairs, since one may
draw more current than another triggering the bulb sensor.

Try removing the tail lights a set at a time, until the bulb out sensor is happy.
Then you find the problem. The sensor can trigger with both bulbs lit, but one
bulb will be drawing more current.

Bill

Try moving the headlight switch to the parking light position to make sure it is not one of the headlights.

You might want to take the bulb holder out of the trunk lights and clean the bulb base and holder.

The bulb out indicator works by noting a difference of voltage used from side to side of car.

The brake lights will only trigger the warning when the brakes are applied.

Are you sure it is the bulb out and not the rear fog light indicator? Bulb out warning has an "X" through it.
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