Adding A 7-Way To A 2014 Mercedes-Benz GL63 AMG
Updated 08/07/2025 | Published 07/01/2025
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Question:
I have a 2014 mercedes GL63 amg. I want to put on a trailer hitch light to use as a running,brake and reverse light. I wanted a plug and play deal but, Im having a problems finding a flat 7 pin square end to regular 4 pin harness. Do you have the parts or an alternative solution? Thank you for your time and effort.
asked by: James B
Expert Reply:
Hi James!
We can get you squared away, but there are not going to be any plug and play options available for your 2014 Mercedes-Benz GL63 AMG, unfortunately.
You will want to start with a 4 flat, like the Tekonsha ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit # 119250KIT to get most of the functions working (turn signals, brake lights, and running lights). This doesn't require splicing or cutting into your wires, so it recommended. From there, you will want something like the Buyers Products Trailer Connector Adapter - 4-Way to 7-Way RV and 4-Way Flat # 337TC1474P. The 4-flat will plug into this and you will then need to connect the yellow wiring with the butt connecter to your reverse light wire with 12 gauge wire # 12-1-1 (there is not a way to do this without cutting and splicing). You will need to use something like a Hook Probe Circuit Tester # PTW2993 to find this wire.
I know this is a lot more involved than you were hoping, and for that I am sorry. Are you wanting to pull a trailer?
Product Page this Question was Asked From
Reese Trailer Connector Adapter w/ LED Circuit Tester and Dust Cover - 7-Pole to 4-Pole or 5-Pole
- Custom Fit Vehicle Wiring
- Wiring Adapters
- Universal Fit
- 7 Blade to 4 Flat
- 7 Blade to 5 Flat
- Plug Only
- Reese
more information >
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Lazer S.
8/7/2025
Hi James, Did you get a chance to try out the wiring harness and connector adapter for your Mercedes? I'm curious to know how it worked out for you since it seems like a bit of a project. If you’re still working on it or need more help, feel free to reach out!