One would anticipate the timing circuit for the courtesy and boot light has been designed with tungsten filament lamps in mind. You MAY get some joy by wiring a resistor in parallel with the courtesy lamp. If - say - this was originally a 5W filament lamp, a 30ohm, 5W resistor may help. Make sure the connections are properly insulated and that the resistor is mounted away from items that may be affected by heat.
HTH
July 2016
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