Let me say that I don't know what is causing your issue, but I did have a similar problem. When I changed my bumper, I installed the fog lights that came with the bumper and wanted to use the stock fog light switch, built into the headlight switch, to control the aftermarket headlight bulbs. I wired the stock fog lamp wiring to the aftermarket fog lamp relay. All the stock wiring did was close the circuit to allow power to go to the fog lights. This setup worked for a short amount of time, then I started having issues. What I found out was that the stock wiring was very sensitive to the load on the circuit. The relay was not enough load, so the relay under the dashboard on the passenger side would start clicking and the fog light indicator on the headlight switch would get very dim. I finally decided to use one of the upfitter switches instead, and have had no issues with my fog lights. If you are going to use the stock wiring, I would suggest that you put the stock flasher relay back in and just use the resistors with the LEDs.

Oh, and I will second what the poster above me said. SSCULLY is probably the best source on this website for electrical issues.

 

Some how I missed that above, thanks for confirming the answer.

When will you have time to reinstall the factory bulbs ?

The other thing instead of reinstalling the factory headlamps is to do the fog lamp mod, changing the ground from the high beam element to a ground pin.
This removes the interaction of the fog lamps with the headlamp bulbs.

https://www.f150online.com/forums/el...aybe-04-a.html

 

Appreciate all the info guys freekyFX4 that sounds very similar to whats been going on.

Reinstalling the stock bulbs in a little while, and I picked up some load resistors the other day. Should I put load resistors on the front too or just the rear good enough?

 

Well I was trying to install the load resistors in the rear but the ones I got from auto zone are crap. Anyone have a good recommendation for a set of resistors.

I put the stock bulbs (rear) and flasher back in and I believe it solved the problem.

Its just weird how it had been working for so long and then it started happening.

Thanks again for the input everyone, and SSCULLY heard about that mod I might try that out later on, it looks fairly easy to do but with me you never know Thanks.