I have a 2015 f150 5.0 xlt and installed led switchbacks for the front turn signals, rears are already factory led (302a).
link to the switch backs.

LIGHSTA CANBUS Anti Hyper Flash 7443 7444 T20 992 7444NA Switchback LED Bulbs Dual Color for Amber Yellow Turn Signal, White Daytime Running Parking Lights, No Load Resistor Needed(Pack of 2) https://a.co/d/8Pfm0QL

the issue im having is the switch backs work as designed without the engine running, I can have high,low and fog on and they change to amber and flash like they're supposed to. If the engine is running they either flash white only or go dim-bright-amber-off. Its not hyperflashing and they work properly with the engine running and no other lights on. Does anybody have any ideas on how to get them to work. I have forscan and have been playing around with the outage parameters with no luck. Any help would be appreciated. Thanks

 

Did you ever figure this out? I am having the same issue on my '18. The white light "strobes" when engine on and light switch in parking or headlights on position, but amber signals work fine and everything works fine with engine off.

thanks

 

What brand? My Diode Dynamics have been flawless.