What year is this? The lights are BCM controlled, I thought. No relays.

 

Silly me. I thought he was talking about 9 to 14 since that is the subject heading. I didn't check all 5 years but 2009 has FETs so maybe all.

 

check connector plugs to the tail light for corrosion in the contacts

 

I have tested the wires going to the plugs I'm getting nothing on the high side. so that tells me it's not a plug issue. I also know that from the engine bay the relay is not clicking like it should be in order to activate the flashing affect. So now I'm looking from The steering wheel to the engine bay. My assumption is it has to be something in between the steering wheel and the fuse panel in the engine.

 

So what year truck and model are you working on?
If it has a BCM, you may need to use Forscan to look for codes.

 

2011 XLT Crew Cab. It has a BCM (Fuse Panel) on the passenger side kickpanel

I would really appreciate some help on this. I have ran forscan to add remote start. Im very new at it but I’m open to learn.

Thanks

 

GY-BN? Gray, Brown Stripe? That is the color wire that goes all the way from the Fuse panel in the engine bay back to the drivers side tail. I tested that wire and I’m not getting a signal, but I’m also not hearing a clicking sound from that relay. Like I said I can hear the clicking sound from the passenger side relay. My assumption would be the relay should be clicking as well.

@Spiky

I appreciate your help on this!

 

Forscan is what I would do next personally.

So, I'm posting the explanation for the stop lamps and the BCM type of codes you might get.
If you have Forscan, I would check the BCM for a "U" code or any codes really.
The BCM can shut down a circuit if it detects a short. Sometimes you have to go into the BCM with Forscan or have the dealer reset the BCM and circuit after the repair.

Or
I'm posting a picture of the connector at the BCM and if you are inclined, I would take my meter and put one probe on the back side of pin 12 gy-bn wire on connector C2280D and the other end on a good ground.
Apply the brake pedal and see if you are getting 12 volts out of the BCM.
Let us know what you find.

 

@Newbie 5

One thing to add. The turn signals on the left mirror and the front left lamp both work when hitting the turn signal.

 

So reading normal operation above, that tells us the fuse power is working.
The way I'm reading it, it appears the front light and rear light are on two seperate circuits.
So you need to check the BCM for a DTC code pertaining to the left brake light which may need to be reset.
If all is well in with the BCM then it would appear to be a bad wire or connector.
Looking at Spiky's print I think there are two connectors along the way to the rear brake light which we can post to help you if needed.

If you don't have Forscan available to you, I would try to check for power at the BCM for pin 12 (I think it was ) while the turn signal is on or brakes applied.
That said if you have no power there it brings us back to the BCM and DTC's.