How do you replace the light bulb in a 1999 expedition running board?
To replace the light bulb – you need to remove the headlight. To remove it, you need to disconnect the chip from the headlight and fold the bracket under the headlight. Moreover, it is more convenient to do it on the left side. In the article https://bestportableproducts.com/3057-bulb-vs-3157/ you can see which paws are better to use.
On my 1997 Expedition I found a rubber boot directly underneath the forward light in the running board. There is one phillips head screw at the front of the boot. Just remove the screw and pull the boot down far enough to expose the plastic socket that holds the light bulb. Turn 1/4 turn counter clockwise to remove the socket and bulb. The bulb is a small wedge base bulb that pulls straight out (it’s a smaller bulb but identical to the 7 watt wedge base bulbs for your exterior walkway lamps). Just pop in the replacement bulb and push the socket back into it’s hole, turn clockwise 1/4 turn to lock it in and replace the screw to hold the boot in place. I used a Sylvania 194 (4.6 watt) replacement bulb–not sure if that’s exactly right but it works!
