Trailer Hitch and Wiring for 2015 Mercedes-Benz GL550

Updated 09/17/2018 | Published 09/15/2018

Products Featured in This Question

Curt Trailer Hitch Receiver - Custom Fit - Class III - 2"

(21)

$481.43

ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit

(522)

$192.64

etrailer Ball Mount Kit for 2" Hitches - 7,500 lbs

(1375)

$88.82

Equal-i-zer Weight Distribution System w/ 4-Point Sway Control - 10,000 lbs GTW, 1,000 lbs TW

(840)

$705.88

Question:

Recently purchased a 15’ GL-550 4matic. The vehicle was not equipped with a hitch/towing package. We replaced the vehicle from a Suburban as we do a lot of towing such as enclosed snowmobile trailers etc 5,000+/- ish. Salesmen checked with the service felt they told him it be more cost effective to go aftermarket and have a local hitch place do it...for a grand. We took his word for it and bought it. Now I’ve done some research and I have the following questions with a Curt hitch. 1. Will the anti-sway control work if i purchase a curt hitch and wiring harness? I’ve read issues with the SAM unit? Will the vehicle recognize I’m pulling? 2. does the curt hitch stick out so you see it? The factory units are hidden under the bumpers from what I gathered. The dealer wants $3,000 to do a factory one....$1,050 for the hitch and 2k labor to run the wires and install. Yikes! Another concern is vehicles that come not equipped with a hitch from the factory does that mean no transmission cooler?

asked by: Augie

Expert Reply:

Curt 2-inch hitch # C13190 is a confirmed fit on your 2015 Mercedes-Benz GL550 so long as it does not have the Active Curve System. This hitch is rated for tongue weight (TW) of up to 900-lbs and for trailer weights up to 7500-lbs. According to my research the vehicle itself shares this 7500-lb towing capacity. Install instructions are linked for you.

This hitch will not offer the exact same appearance as a factory hitch; the cross tube will be visible as you can see in the photo from the instructions that I linked for you. Also do please note this hitch is NOT rated for use with a weight distribution/sway control hitch system like # EQ37100ET. If you are referring to aftermarket anti-sway bars made for the car I cannot confirm compatibility since hitch makers do not test fit their hitches with all of the available aftermarket products.

You can find out the specific equipment that was installed at the factory, such as a transmission cooler, by having a dealership run the car's VIN. This will tell them all the factory equipment on it. There is no standard definition for what is included in a vehicle's "tow package". For some autos that may be a hitch only, or a hitch and wiring only, or both of those things plus a supplementary transmission cooler. It depends on the specific auto maker and vehicle so your nearest dealership can be consulted for clarification.

A defective signal acquisition module (SAM) can cause issues such as the fuel gauge or lights not working, fuses blowing or battery drain, among other reported issues. I am not aware of problems with this optional feature caused by installation of an aftermarket hitch.

The wiring harness we recommend for your GL550 does not directly connect to the car's wiring. The ZCI 4-pole wiring kit # 119250KIT recommended simply clamps over the car's wiring and detects the required signal with magnetic sensors. You may also care to use our Ball Mount Kit # 989900 which includes two ball mounts, two hitch ball sizes and a pin and clip.