Both tail light are mostly out but some times they come on.

[Tiwaz]

So.... I have both of my tail lights that do not come on, they have LED bulbs, the other lights (turn and stop) have standard bulbs they work just fine. So I turn on the lights in my parking lot and nothing, some times I have gotten out of the truck at a red light and both of my lights were on, I don't know what I am doing.... literally

 

[thoner7]

Aftermarket lights? Or just aftermarket bulbs? Swap them back to OEM and I bet they’ll work. I had a similar problem recently

 

[Tiwaz]

The weird thing though is that if it was about the tail light assy or the bulb themselves, they would not always quit (or light up) in tandem, meaning that when this problem happens or cease to happen it's always the both of them together so I believe it could be something else.

 

[Sganderson]

Could be a ground issue. It is my understanding that led’s require better ground than their halogen counterparts.

 

[thoner7]

The weird thing though is that if it was about the tail light assy or the bulb themselves, they would not always quit (or light up) in tandem, meaning that when this problem happens or cease to happen it's always the both of them together so I believe it could be something else.

I had a fault in one tail light. It affected both. Not every time, but most times.

it’s the easiest thing to check. Just swap the wires over to a different tail light(assuming you have one)

 

[Mogman]

So.... I have both of my tail lights that do not come on, they have LED bulbs, the other lights (turn and stop) have standard bulbs they work just fine. So I turn on the lights in my parking lot and nothing, some times I have gotten out of the truck at a red light and both of my lights were on, I don't know what I am doing.... literally

Put the standard bulbs back in.

 

[Awol]

I had a similar issue with the tails but coming on at all, sometimes flickering, or staying on constantly.

Traced it back to a faulty brake light switch. There was no way to adjust it to the point where they would work properly. A new switch solved everything.

 

[Tiwaz]

As it turns out all I needed to do is squeeze the sockets a tiny bit where the bulb fits very snug even before turning it (The weird question remains though: why were they failing in tandem..?) I did that on both sockets and did not have a problem since.