Are any of the LEDs connected to the turn signal switch ?
Are you trying to flash a filament directional lamp and a LED directional lamp at the same time?
Like a hybrid,
Left front directional filament lamp
Left rear directional LED lamp
I don't know if you can mix match LEDs lamps and filament lamps on the same circuit.
At least when using a flasher in the circuit..
When pulling out the headlight switch how does the front park and the rear tail lamps look?
Is this how you have the truck lamps configured?
Check attached
xfiles
