Well your first problem is that you like Fords. j/k. Did you check the fuse under the seat?

 

We'll get rid of your FORDS first and life will be easier..........haha!

Where they working after the undertail swap? Maybe you shorted something out somehow installing new bulbs. Did u check fuses?

If its only one side not working it's usually a bad bulb. But if both sides are not working it's a fuse or wiring.

F4i's are known to have bad solder connections in the starter switch box on the right bar. When u hit the starter button the lights go out to save batt power, but sometimes the starter switch has bad connections and causes headlight problems. Take the two screws out of the bottom and take the top cover off and you'll be able to see if a connection has come off.

 

I check the fuse under the os There more than one where os That Is box located at and easy on the fords Haha

 

Possible loose connection somewhere after pulling the front fairing.

 

Make sure the starter button is all the way out,

that will cause the lights not to work. good luck

 

HUH??

 

i checked the fuse under the seat it is good and i dont were the starter box is and is there only the one fuse or is there more

 

My headlights didn't work one night and it was because

when I started it the button didn't come back out all the way,

Give it a little tug. I sprayed switch cleaner in it so it

doesn't stick any more. Heard it happens alot.

 

yup that happened to me, so you might wanna check out your starter button. I just sprayed a little wd40 in my start button to get it to come back out and never get stuck again, however i was informed that switches and wd is kinda a hazard because wd is flameable. So maybe you can use a better form of oil to loosen it up