For 4.0 motor cars Ford used economical and up-to-date bulbs. Popular base BAY15D was used in this system, but power should be at 21/5 W. It all provides normal work of Ford Explorer 4.0 electrical system. Every lamp in Explorer has average voltage of 12 V. You can’t drive your Ford Explorer with badly working stop lamps.
In 2001 year of production it’s only BAY15D type with exact voltage of 12 V. Recommended by Ford lamps are the best choice for Explorer 4.0. Installing in 1997 Ford Explorer other lamps will cause damage to electrical system.