Freightliner cascadia turn signal

Have you replaced any on the tractor with leds?

 

Replace the led with the same kind of bulb the truck came with, humor me.

You said you swapped out trailers, every one of them isn't bad on the same side. You said u replaced the pigtail. That leaves just the truck as a possibility.

Put standard bulbs back in, or replace every one of them with led, at a dealership, because they have to reprogram the computer for leds to work.

But first, put a standard bulb back in, your problem, may magically dissappear.

 

If they were already led, don't bother. I didn't think led truck tail lights were even an option in 2011.

It is crazy but the truck computer needs settings changed when switching from incandescent to led. It's something to do with the current the old bulbs draw, vs, the low current leds draw in the SAM or CAB module.

 

Go to your aux. sam (fuse box under hood driver side fire wall) one of your check your fuses. One of them powers a relay(right and left have separate relays) If the fuses are good then the relay is bad. Have had numerous bad relays. Flip flop right and left relay to test. Relays are available at any auto part store.

 

I will vouch for that.(I think.) I pull in the shop with the tractor marker/turn signal bulb burned out. A mechanic replaces that bulb with an led light. LED light doesn't burn. The mechanic leaves and goes gets the head mechanic. Head mechanic says driver, turn the kill switch off, then on. (I'm thinking there is no way the kill switch is going to make that led light burn.) Sure enough, the new LED burns. The head mechanic explained to me that the computer has to "recognize" the new LED for it to work. Unreal.