Trailer Lights STILL Not Working | Replacing Truck Socket & Installing a Junction Box

The trailer wiring saga continues at Merryvale! In this video, Santa Craig Cringle keeps chasing down trailer light issues on his equipment hauler, making some good progress — but not quite solving the puzzle just yet.

This round of troubleshooting includes replacing the 7-pin trailer light socket on a 2007 GMC Sierra 1500 Classic, and upgrading the trailer wiring with a new junction box harness. He also uses a simple test light to trace electrical signals on the truck side.

Whether you’re into DIY trailer repairs, GMC Sierra mods, or just like seeing someone learn by doing, this one’s for you.

🛠️ What’s covered:
• Replacing the truck-side 7-pin trailer socket
• Installing a trailer wiring junction box
• Using a test light to trace connections
• Notes from the struggle bus (but hey, it’s progress)

🎯 Featured tools & parts:
• Replacement 7-pin trailer connector (truck-side)
• Pre-wired junction box trailer harness
• Test light probe

💬 Got wiring wisdom? Drop it in the comments — Santa Craig’s still learning and would love your input!

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00:00 - Video opening sequence
00:37 - Intro & trailer troubles recap
00:58 - Checking the old truck socket (GMC Sierra 1500 Classic) and trailer wiring.
01:43 - Replacing the truck side socket.
03:22 - Testing the new truck socket with a test light.
04:58 - Removing and replacing the old trailer wiring harness.
07:58 - Wrapping it up. Did it help?
10:00 - Outro

Disclaimer: I’m not a professional mechanic or trailer technician — just a homesteader learning as I go. Always reference your vehicle and trailer manuals, and consult a certified technician if you’re unsure about any steps. Safety first, friends!

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