GL450 trailer hitch installation




Update 4/30/15: I received my new $166, including shipping, Curt 13102 trailer hitch from Ebay today and installed it in about two hours . I am very happy with it as it appears to be good quality and the install was pretty easy.
The $55 luggage rack cross bars seem to get good reviews too.
Last edited by 1xsculler; Apr 29, 2015 at 03:41 PM.

Everything installed pretty well. MY $64 question is that the strengtheners/frame rails (2, one on each side) appear to bolt onto sheet metal - and not especially thick sheet metal. I'm concerned about strength. Am I missing something?

The Best of Mercedes & AMG

This was everything that came with it. Heavy duty beam for each side, including wiring. I thought it was going to be different, since on other peoples' posts I did not see exact one and the extra parts. Questions...
1. Anyone have ideas on the extra items?
2. Do I need to disconnect battery when connecting to rear SAM? (Per dealer's checking VIN, I was told that I did not need new SAM. It does have a spare plug space).
3. Are there detailed instructions, with illustrations?
4. When I take the bumper off, do I need to disable the sensors? I want to make sure that nothing gets messed up. Thank you!
5. One of the wires is ground, another plug goes to rear SAM and two fuses. I am not sure what slots the fuses go into go into? There are many different colors.
I have a gasser; but I’d be a bit hell to the no towards towing something with a high 6k weight (it’ll be much more when loaded) behind a GL.
Not that it’s any kind of comparison, but my GL 450 felt very unsettled and pushy when towing a 5k camper trailer, something my 3/4 Chevy wouldn’t bat an eyelash at.
But that’s what you have and you make do - and make better. Do your research on which rear air bags can withstand that kind of load as well.
I know this is very late, but is it any chance that you still have pictures of your brake controller setup?
If so, can You email some to me, please? Thank You
Glenn
glennlindh@hotmail.com
Last edited by theswede; Dec 25, 2021 at 01:41 PM.
Curt Echo Bluetooth trailer brake controller - no wiring, just plug and play. Works just as good as a wired one minus the risks of bad wiring.
the only con I can see on the gl is that the 7-round connector angles slightly downward, which makes this plug in controller angle downward as well.
"While coding, the dealer needs to add vehicle code "550" to the data card, then SCN code the entire vehicle to allow for the new data code. This code is for the Trailer Hitch, which is required to exist during coding so that any necessary ECU's are receiving the proper info from the Rear-SAM. This allows the car to look for, and expect, the extra load from the brake/turn lights and relay that info to the rest of the control modules on the vehicle (ABS/Traction, Front-SAM, Instrument Cluster, Gateway, etc). We have been manually coding the Rear-SAM to expect code 550, but that only codes the Rear-SAM, not the rest of the control modules.
I use DataMB.com to find the entire data code list for the cars, if you wanted to take a look yourself. I think it's pretty cold to see all the different build codes/factory options/etc.
I have attached a .PDF our software company sent to us, a TSB from Mercedes-Benz that illustrates the necessary steps that must be taken to get the factory harness to work on a car that was not originally equipped with the Trailer option (550). Please note that it does want a new electric fan installed that is compatible with the trailer. I assume this is to increase fan output while towing, to make sure engine temps stay low. The required vehicle documentation updates start on line 19 of the PDF."
Unfortunately, I had taken to one MB dealer who said they would program and figure it out. They did not and still charged me.
I just had to take to another MB for proper programming and they followed the instructions and it worked. Hope it helps.
When the trailer wiring is installed in same fashion as OE Mercedes, the vehicle can ...
Detect presence of trailer when it's electrically connected.
Provide bulb out warning for trailer bulbs
Connect to and operate electric trailer brakes assuming you've added an aftermarket brake controller (only solution)
The vehicle normally lowers the suspension (Airmatic feature) at highway speed to provide better aero/fuel economy. ... this process doesn't occur when trailer connection is detected
If your X164 is very early production, you require replacement rear SAM. Later models not.









