Parts Needed to Install Redarc Tow-Pro Elite Brake Controller on a 2015 Mercedes-Benz G550  

Question:

Expert Reply:

To install the Redarc Tow-Pro Elite # RED44FR on your 2015 Mercedes-Benz G550 you're going to need to a 4-Way wiring kit like the Tekonsha ZCI # 119250KIT as well as our Universal Installation Kit # ETBC7.

The ZCI uses special clamps that sense when the different trailer light functions need to be activated and then it pulls power straight from the vehicle battery to power the trailer lights. This keeps you from cutting your OEM wiring or overloading your vehicle light circuits.

The ETBC7 kit gives you all of the extra wiring and connections you need for a fully-functional 7-Way so you can utilize the brakes on your trailer.

The hardest part of the install will be making your connections for the brake controller. You'll use some wire from the ETBC7 kit for the power, ground, and brake controller connections but you'll need to find and splice into the cold side of the stop light circuit on your vehicle. This means you have to use a circuit tester and find the wire that only gets hot when the brake pedal is pressed. This tells the Tow-Pro Elite when to send power back to your trailer brakes.

If you'd rather avoid splicing into your OEM wiring or you can't determine which wire needs to be spliced into we also have the Universal Stop Light Switch Kit # RM-751000 which gives you that function by installing on your brake pedal system and sensing when the brake pedal is pressed.

We don't have installation videos of any of these parts on a 2015 G550 but I've attached review videos for each part for you to check out.

expert reply by: Jon G

0

Pin Out Diagram for Vehicle Side 7-Way Connector
(click to enlarge)

Blair S.

5/26/2022

The car already has the 7 plug trail plug installed will I have to tap in it

Jon G.

5/26/2022

You can try poking around under your driver's side dash but from what I could find in my research it looks like Mercedes-Benz doesn't have provisions for a brake controller on your 2015 G550 even if your 7-Way is from the factory. If you can find OEM wiring, great. If you can't, then I recommend installing the # ETBC7 wiring kit to get all the wiring you'll need. What you can do is cut off the wiring at the back of the OEM 7-Way on your vehicle then cut off the 4-Way on the ETBC7 and splice the wiring together per function. It might help to note what pin the wiring on your current 7-Way is ran to so it's easier to make your connections. Attached is a diagram of which functions are on which pins for you to reference.