ODI opened this investigation based on 24 complaints alleging that the electrically heated driver or passenger seat sparks/overheats.DaimlerChrysler believes the failure is due to one of two factors:the stitching operation on the seat cover may cause the sewing needle to sever some strands of the wire heating grid in the seat, or a poor solder joint/wire connector fails due to improper processing or long term overstressing.the ignition switch and the seat heater switch must both be turned on to power the seat heater.complainants report that when overheating occurs, switching the heater off also stops the overheating.the failure cannot occur in an unattended vehicle with the ignition switch off.ODI finds that the 33 fire allegations are reporting very localized overheating(photos of damaged seats show holes the size of a pencil or less).there are no reports of sustained combustion and no reports of other fire damage to the vehicle.the injury allegations are reporting minor injury.no consumers required medical treatment (physician care).there are no allegations of loss of vehicle control due to failure of a heated seat.a safety-related defect has not been identified at this time and further use of Agency resources does not appear to be warranted.accordingly this investigation is closed.the closing of this investigation does not constitute a finding by NHTSA that no safety-related defect exists.the Agency reserves the right to take further action if warranted by the circumstances.
