Some of us (myself included) have tackled the wiring harness install. If I couldn't do it myself, I think it would be too expensive. It's really not hard, but it is time-consuming and there really aren't good instructions. To answer your question about what needs to be removed in the interior, you need to remove the non-door panels on the passenger side, the door sills on the passenger side, the center row of seats, the front passenger seat (I left it plugged in, just unbolted), both front kick panels, and the glove box. I had mine apart three times as I tried to get all the correct harnesses and controller. If you follow the list L-L posted above, you can just do it once! I put the harness in place, drove it to the dealer with the interior apart, and had them plug everything into the correct places & program it.

I'm towing a 5000 lb sailboat. Tongue weight is 400-600 lbs (depending on how we have the boat loaded). We are a family of four (both kids are adult-sized) and with gear for a week, we're loaded up. The airbags pump up to keep the rig level and I haven't experienced excessive tire wear. A straight axel would be better for keeping the geometry right, but that's a concession I make for the smoother ride and better handling. I only have about 1500 miles of towing on this rig. We towed the same with our 2006 ML500. Similar air suspension on a smaller rig. We had a least 5000 miles of towing with that one. The only issue we had was a broken fan belt that had a piece wrap around the fan. Replacing the belt was easy, but I wish I would have realized some of it was wrapped around the fan before we were in downtown Seattle traffic. The truck was telling me something was wrong, but I thought it was a leftover code from the broken belt. Always listen to your truck (and your wife)! We had 200,000 miles on it when we traded it in for this 2015 GL350.

I love the factory sway control. We were at the towing limit of that ML500 and it always performed very well. When we passed a semi or a gust moved us around, it always settled right out. I wanted that same peace of mind with this one. We all have different uses for our rigs. So read a lot here, ask questions, and make the choice that's right for you.

Jeff

 

Wiring is not that terrible...what was hard was to get the SAM Control Unit out for that single cable that needs to be connected on one of the plugs...It needs a lot of patience.

Jeff, do you get the Trailer Camera Option when in Reverse? If yes, did you have to enable the "RVC Trailer Mode" in the Hidden Engineering Mode?
I didn't have the option to choose the Trailer View when in reverse. I enabled the RVC Trailer Mode in the engineering menu and then it gave me the trailer icon on the screen. But even if I select the Trailer Camera option, the guide lines do not change...basically nothing changes. I am not sure if I have to change the camera type in the engineering mode as well. Maybe the GLs without the factory towing pack pre-installed have different cameras...just a thought.

Any idea what could be the reason it is not showing me the trailer view even though it gives me the option to select it?

 

I'm pretty sure the camera on the hatch comes on the same way it always does. I don't have a trailer at the house right now, but I have the trailer adapter with the resistors for recognizing LED trailer lights. I'm pretty sure the truck thinks a trailer is attached when I hook that up. I'll go try it.

Jeff

 

I plugged it in and it recognized that a trailer was attached. When I put it in reverse all the cameras turn on just the same as when a trailer isn't attached. I didn't know there were any other options, but I just watched video. I can see how that might be handy. If you figure out how to enable it, please post so that I can give it a try.

Jeff

 

Thanks Jeff. Even without the trailer hooked up, on reverse I still get the option to select the "Trailer Hitch" guidelines instead of the "Regular" guidelines"

But with or without the trailer hooked up, the guidelines remain the same.

 

On reverse, if you turn the comand knob right to select the "suv with trailer" icon, do you still have the same guidelines on the screen?

 

I don't have the "suv with trailer" icon.

Jeff

 

To get the icon, I entered the engineering mode (hang-up + 1 + # buttons simultaneously until it enters)....then HW Settings (7)...then HU Parameters (7.7)...Scroll through the pages until you find the RVC Trailer mode (mine is #24).
I just enabled RVC Trailer Mode and exit the engineering mode. For the function to become available, a system restart is required....thus just lock the car and wait 5-7 minutes.

 

We had a factory trailer hitch installed by a local indy last year. I think we paid just under $2k parts and labor but the job was way more labor intensive then they were anticipating. We both assumed that our 2013 GL550 was pre-wired for the hitch and it was not. They needed an additional harness or two and the interior had to be taken apart all the way up to the dash. They kept it an extra day or two and I'm sure many more hours were spent on it then we were quoted/paid for. The parts were just under $1k and I think we paid about $1k in labor. I can look at invoice for part numbers if that helps anyone but there were some additional harnesses needed that I don't think they charged me for.

 

Hey Yeffsy....any luck with the reverse camera trailer view?
I didn't manage to figure it out yet.

 

Sorry, I haven't messed with it yet. Our GL350 is currently at the dealer getting the emissions update, tires, alignment, and transmission service. I'm supposed to pick it up this afternoon or tomorrow. I should have time to get it into the engineering mode, mess with the settings you suggested, and give you a report tomorrow.

Jeff

 

Thanks Jeff. I will keep trying to figure out too. I hope that the reverse camera on GLs without a factory towing pack, is not different than the rear cameras installed when the towing pack is factory installed.
I got mine back from the dealer...emissions done...filed the claim and submitted the repair order etc to MB. About 4 days later, I checked my VIN here (https://bluetecupdate.mbusa.com/home), and it shows that the installation is complete and extended warranty applied. It has been about 2 weeks now and still no check from MB.

 

Question on the OEM hitch vs the Curt hitch, how much lower does the Curt hitch hang? I'm picking up a 2015 GL550 and need to add a hitch to pull 2 SeaDoos. It seems the Curt hitch sits a lot lower than the OEM one.