Turn Signal

My turn signal works when the lights are off, but when the lights are on the rear acts like the bulb is burned out.

Any thoughts would be much appreciated.

 

I havent, just bought the truck though

 

Take it back and let them fix it.

 

Could be bad wiring, defective bulb, or the fuse needs to be replaced.

 

What do you mean? As in the tail light doesn't glow, or as in nothing happens at all?

 

So, when your turn signal bulb burns out, the flasher for which ever side is out flashes very quickly, you go back look at the tail light and the bulb is not flashing. This is the situation when the headlights are in the on position. When the lights are on for night time driving the turn signal indicates the bulb is out. However, when the headlights are not on daytime driving the turn signal works properly...make sense?

 

Just to confirm, it's your rear signal lights that do not work when the headlight switch is in the on position? If so, it sounds like there is a short between the taillight circuit and the signal circuit. If that's the case, start by replacing the affected light with a known good bulb. If it persists, start inspecting wiring and connectors for signs of damage/poor connections.

 

This
I understand OP just bought this truck, BUT profile is listed as a 2017, so not new.
Does this truck have any aftermarket doodads, or is it strictly 100% stock?

Look first, where the human was last

 

Grounds, grounds, grounds

 

Just making sure it isn't as simple as one filament being out and just needing a new bulb is all. Have you confirmed that the previous owners didn't install LEDs? I feel like this is less likely, but could be a cause nonetheless if they didn't get the proper bulbs or use the proper resistor if the bulbs required it.