Tailgate lock and 3rd brake light not working after tailgate replacement

[Galveston]

My tailgate was replaced due to corrosion, now my power tailgate lock and 3rd brake light don't work. There is no noise from the lock motor, and all other lights work. The tailgate still locks with the key.

I removed the two panels on the inner tailgate and verified all wires are connected. I also checked fuses 20, 26, 28, 29 (interior lights/controller, exterior lights 1/controller, power locks/controller, exterior lights 2/controller) and all look good. The reverse camera still works & is on the same harness. I assume the camera , 3rd brake light, and power lock all share power, can anyone confirm?

Is there anything else that I can check to avoid another trip to the dealer, maybe a fuse I overlooked?

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[Gvsukids]

Is there anything else that I can check to avoid another trip to the dealer,

What's wrong about having them correct something they didn't install correctly?

 

[Galveston]

What's wrong about having them correct something they didn't install correctly?

Only the 2hr round trip. If it were closer I wouldn't hesitate.

 

[Texbaz]

who's they? was it a dealer,independent body shop,regardless if they installed something they should have ops checked it. Pretty hard to understand the installer not doing a simple functional check before they say here ya go.

are the lock and taillight from your old tailgate? Is this a used tailgate you bought from an independent shop.

 

[DylanM]

A quick look at the wiring diagrams shows the backup camera coax uses different connectors than the CHMSL and tailgate power lock actuator. Seeing as how you've already checked the wiring inside the tailgate, I would next take a look for unplugged connectors inside the left rear bed side where the tailgate harness passes through and heads toward the front. You should be able to see in there either looking up from below or through the rear after removing the left taillight... scratch the last bit, the harness runs too low to see from the taillight opening. I just took a look at my truck and there are two connectors to be found underneath the bed just behind and outboard of the spare tire, then another behind the rear of the left rear wheel well.

 

[Sweetums]

My tailgate was replaced due to corrosion, now my power tailgate lock and 3rd brake light don't work. There is no noise from the lock motor, and all other lights work. The tailgate still locks with the key.

I removed the two panels on the inner tailgate and verified all wires are connected. I also checked fuses 20, 26, 28, 29 (interior lights/controller, exterior lights 1/controller, power locks/controller, exterior lights 2/controller) and all look good. The reverse camera still works & is on the same harness. I assume the camera , 3rd brake light, and power lock all share power, can anyone confirm?

Is there anything else that I can check to avoid another trip to the dealer, maybe a fuse I overlooked?

Check the tailgate harness disconnect, it’s the wire that goes from the bottom of the tailgate to the black plastic panel below the bed.

 

[Galveston]

Check the tailgate harness disconnect, it’s the wire that goes from the bottom of the tailgate to the black plastic panel below the bed.

A quick look at the wiring diagrams shows the backup camera coax uses different connectors than the CHMSL and tailgate power lock actuator. Seeing as how you've already checked the wiring inside the tailgate, I would next take a look for unplugged connectors inside the left rear bed side where the tailgate harness passes through and heads toward the front. You should be able to see in there either looking up from below or through the rear after removing the left taillight... scratch the last bit, the harness runs too low to see from the taillight opening. I just took a look at my truck and there are two connectors to be found underneath the bed just behind and outboard of the spare tire, then another behind the rear of the left rear wheel well.

Thanks for the suggestions, going back to the dealer today. Tracing the harness back to the rear wheel well in the daylight, everything seems to be plugged in securely.

My warranty expired while it was in the dealer's body shop for corrosion work (hood, tailgate, windshield frame) - hopefully this won't be a hassle.

 

[Sweetums]

Thanks for the suggestions, going back to the dealer today. Tracing the harness back to the rear wheel well in the daylight, everything seems to be plugged in securely.

My warranty expired while it was in the dealer's body shop for corrosion work (hood, tailgate, windshield frame) - hopefully this won't be a hassle.

There’s a plug just inside the black plastic panel where the harness goes from the tailgate under the bed, it’s there so you can remove the tailgate at home. The loom splits into two plugs, bet you one wasn’t plugged in correctly or a dealer monkey bent the pins

 

[Galveston]

Scratch that, I thought I'd check one more time to avoid the drive. There are two connectors at the tailgate disconnect, body side. The top one felt snug, but disconnecting/reconnecting fixed the problem (it took quite a bit of force to get it to click in).

Much better done in my driveway than driving. I'm waiting for a call back to tell them about it, along with other issues I didn't mention here: fresh scratch on a fender, deep gouge in the inner tailgate panel, and they didn't reinstall the anti-theft tailgate bracket - just left it & the bolt in the bed.

 

[Galveston]

There’s a plug just inside the black plastic panel where the harness goes from the tailgate under the bed, it’s there so you can remove the tailgate at home. The loom splits into two plugs, bet you one wasn’t plugged in correctly or a dealer monkey bent the pins

This was it. It seemed connected, but disconnecting/reconnecting the top plug behind that panel fixed the issue. It took quite a bit of force to get it to click in. Saved me another trip to the dealer, thanks!!

 

[Sweetums]

Glad it saved you the drive.

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