2017 Yukon taillight issue

[Keil]

My 2017 Yukon brake light stopped working, used YouTube and repaired it. After about a year the left rear turn signal stopped working along with right rear running light. Swapped right rear to left rear and running light worked but not turn signal so it doesn't seem to be the actual tail light assembies. Any ideas?

[newdude]

The rear lighting is all BCM controlled.  There are circuits from the BCM that pass through the underhood fuse block, which then all feed to the body side plugs to the tail lamps.  You'd have to test the BCM output of each circuit and make sure the BCM is doing its job, then test the ciruicts at the tail lamp plugs to see if they are working.  If you aren't getting power back there, you'd have to test the output side of where those circuits come out of the underhood fuse block.  

 

This all said, 2015-2017 are known trouble years for defective tail lamps.  

 

 

[asilverblazer]

20 hours ago, Keil said:

My 2017 Yukon brake light stopped working, used YouTube and repaired it.

Which brake light quit?

 

20 hours ago, Keil said:

 After about a year the left rear turn signal stopped working along with right rear running light. Swapped right rear to left rear and running light worked but not turn signal so it doesn't seem to be the actual tail light assembies.

You plugged the left rear assembly into the right rear position, activated the right signal and the left assembly signal (in the right position) did not flash? That sounds like the assembly is defective.

 

Running light failure on mine was intermittent, you could bang on the assembly and it would work/flash with each hit. 

[SieClan Yukon]

Have a 17 Yukon with the common tail light issue.    Purchased new tail lights and the same thing no running/park light on passenger side. Verified with known working oem drivers side same thing.     Tried using a test light gray/brown wire was repaired at some point and has power at the pin. Is there a separate ground for the park lights or something else that would not complete the circuit for just the park light?

[asilverblazer]

10 hours ago, SieClan Yukon said:

Have a 17 Yukon with the common tail light issue.    Purchased new tail lights and the same thing no running/park light on passenger side. Verified with known working oem drivers side same thing.     Tried using a test light gray/brown wire was repaired at some point and has power at the pin. Is there a separate ground for the park lights or something else that would not complete the circuit for just the park light?

Did you review the diagram above?

[GMCustomerService]

On 2/27/2025 at 11:27 PM, SieClan Yukon said:

Have a 17 Yukon with the common tail light issue.    Purchased new tail lights and the same thing no running/park light on passenger side. Verified with known working oem drivers side same thing.     Tried using a test light gray/brown wire was repaired at some point and has power at the pin. Is there a separate ground for the park lights or something else that would not complete the circuit for just the park light?

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[SieClan Yukon]

On 2/28/2025 at 8:17 AM, asilverblazer said:

Did you review the diagram above?

Yes.    With switch turned on I have constant power on 309 GY/BN wire at the plug.     I need to get a meter to check voltage.   Everything but the park light works on both tail lights.