jchpd203

I just bought my 2021 F150 XLT Sport 4x4 with the 2.7 ecoboost 3 weeks ago. Last night a made a right turn and the dash indicator blinked faster than normal indicating a bulb out. The bottom bulb on the passenger side turn signal element appeared to be burned out. I pulled the housing and switched the top and bottom bulbs to be sure it was the bulb, and the problem switched to the top so I went searching for the bulb. Internet and it was supposed to be a 3157. Trouble is the 3157 does not fit the socket. The light housing and owners manual indicate a WT217W or WT21W. I gave this info to the guy at the parts store and he could not find a replacement. I tried an internet search and can’t find any bulb with that designation. I trying to avoid going to the dealer but looks like I may have to. Anyone have any suggestions?

Green_Bean

I think I would have a dealer check it out to make sure there isn't any underlying problems. I wouldn't think a new truck would be blowing bulbs this soon.

Blueshound

Does the bulb itself have any identification marks? If you have a picture of it, might help identify.

djfllmn

iTrader: (1)

just checked my parts catalog at work, and tried crossing it on after market websites, looks like its dealer specific, should be under warranty though unless something weird happened

digitaltrucker

Double post:

https://www.f150forum.com/f12/2021-t...b-help-520199/

Steel City 07

It's actually a 4257. Buy 3157 bulbs and shave the tabs off them. I did that with some 3157 LEDs to fit them. For whatever reason 3157s are much cheaper than 4257.

pbergmann

Why don't you just take in to the dealer sometime.
You may be under warranty

jchpd203

Didn’t go to dealer because it was Saturday and only a bulb. 5 min fix for me, a drop off and pick up a day later at the dealer with no loaner even though it was under warranty. Dealer does not have bulb in stock, had to order.

Germansheperd

DO NOT listen to this guy

Germansheperd

Ah yes the “I’m not going to the dealer I can fix it myself in 5 minutes”- days later still broke. So it appears to me if the parts guy ordered the bulb Saturday it would be in Monday. Why would a loaner be needed for a bulb change? You yourself said you could do it in 5 minutes?
Here I will help you. The bulb you want is a 7440/7443. You passed them up all weekend at any Advance, Autozone, O’reilly, Napa.