Which side is this happening on?
I am attaching the wiring diagram where I highlighted the wiring for the left side. It is not much different if this is the right side.
However, I suspect you have an issue with the smart junction box. I suspect you are finding that the lights still work on the side that is working, when you pull the relay because you are pulling the trailer tow relay for that side and not the actual turn signal relay.
This vehicle uses what is called a FET and not a relay. There is a circuit board on the SJB that decides when to send voltage and the FET is there to simply control the current flow.
So again, I suspect the issue is in the SJB. So let's test voltage coming out and if it is a good 12 volts on the wiring going to these lights then you are probably correct that the ground is the issue.
Let me know what questions you have.
Images (Click to enlarge)
Friday, February 19th, 2021 AT 1:29 PM