One problem related to trunk wiring has been reported for the 2004 Toyota Sienna. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2004 Toyota Sienna based on all problems reported for the 2004 Sienna.
Toyota has eliminated the brake lights on the tailgate of the Sienna. The small brake lights that are on the corner of the rear end are not sufficient and will result in a higher number of Siennas getting rearended. The driver rearending the Sienna will take the blame when the Sienna is partially at fault.