jimmyp

Good job, not to bad if your good with hand tools.

jh87

I just installed the trailer hitch for my 2010 GL450. I pick up the hitch at local dealer for $800 plus Tax (SoCal). Installation is not difficult, but I do need to cut the skid plate using a electric shears ($24 from harbor freight). There is one plug that I could not figure it out. There are total of four ends from the hitch itself. One is the ground, no problem there; another one in brown color is the fuse which goes in the fuse box nicely, the largest plug with some kind of lever goes in the rear SAM unit without difficulty. The last one I don't know where to go. There is one empty socket left in the rear SAM units but that plug doesn't fit. Any suggestion?

jimmyp

I just went out to look at mine red wire goes to power, brown is ground, one black plug to sam. The only one left is the green plug and thats for the trailer break if you add one, but just get a wireless one for a little more money. Test it on a trailer and try to raise the truck with the trailer connected it should tell you it cannot be raised then you know it will all work.

jh87

That is what I was thinking too, thanks for the info. It is good to know there is a wireless one for the trailer break. I only plan to use the hitch for cargo box at this point, but definitely will look into the trailer break control in the future. Thanks again.

kuzy13

Jim_Ma,
Could you send me a copy of your installation papers.

Thanks!
Kuzy13

jimmyp

No papers come with it. Get the service guy at dealer to print out a pic of the rear bumper and you will be good. There are 2 bolts for bumper in wheel well, pull carpet in the rear two in the back for rear and two on each side by the side lights. You can just pull the bumper off and set it on the ground without rermoving the parking sensors. It is a easy job when you know where the bolts are. Let me know if you need some pics.

kuzy13

Does any one have any data on the two side members, that slide into the truck. I bought a used hitch and they did not come with it. I would like to fab them.

Thanks
kuzy13

kuzy13

JimmyP
do you have any info on this Matter

Kuzy13

jimmyp

Yes they are two cast iron fram supports that bolt in with 2-3 bolts on each side from insidew the trunck area, I think they are the same for the ml, I think thats what my parts guy said. You need these do not install yet as these have to go in first then the hitch bolts to them.

kuzy13

JimmyP

Thanks for the info! I will check to see if MB will sell them alone?

Kuzy13

gbigpapa

Are you sure that the stability programming applies the trailer brakes? This would certainly have no effect on surge brake trailers. I would bet that the ESP applies braking to the rear vehicle brakes instead.

As I understand it, the trailer brake output on the back of the truck is routed to the harness under the dash (or rear compartment on vehicles built in '06) terminating with a green connector. This connector receives its signal from an aftermarket brake controller and routes the braking signal to the trailer connector.

I'm in the process of figuring out exactly what I need to install a brake controller for my 07 GL450 and I'm still not clear on why the SAM needs to be replaced. My truck provides indication of trailer light status when I have a burnt out light and prevents the high suspension setting so I know the current SAM recognizes when a trailer is connected.

What additional function would an updated SAM provide when using a trailer brake controller?

Fourdiesel

"I neither understand what I know, nor do I know what I understand; but I do know that the more I now know, the less I understand!"

Clearly, surge brakes cannot be compensated by the ESP program since it has no 'knowledge' of when they actually apply. Likewise, the ONLY way the ESP even has a chance of creating stability (absent a pretty exact knowledge of the mass of the trailer) is it's measurement of the towing vehicle yaw rate characteristics under actual stability conditions. According to the sales books I read at the time I bought my GL, the ESP program takes these into account in 'deciding' what to do under pending skid conditions. It is only logical, that, since the SAM unit 'knows' the trailer is there, and has brakes, that it apply those brakes first. Any trucker will tell you of the surprise if he sees his trailer coming 'round to meet the front of his truck - thus he always hits the trailer brakes first. I have never had the 'luck' to push the MB system to it's limits and check it out!

lkchris

Mercedes ESP has NOTHING to do with trailer brakes.

mdadgar

Unfortunately, the SAM unit can't apply the trailer brakes because the 3rd party trailer brake controller does that.

Most of those units are inertial - they look for two things: 1) an active brake light circuit, and 2) an inertial measurement of the tow vehicle slowing down.

The SAM is not in the actual brake activation circuit - it's only in the brake light circuit. The brake controller (Tekonsha Prodigy RF, in my case) is what actually applies current to the brake circuit.

What the SAM is most likely doing is braking one or the other of the tow vehicle rear wheels to counteract yaw.

- Mark

MercedesGL_ftw

Today, I got the tow hitch from LKQ auto parts from a 2007 GL450 and that's the one I have as well.

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.

jimmyp

I did my install on a 2010 they forgot to give you the rear bumper that connects to the hitch, also my frame rails were cast iron peices yours look different. Maybe its a early year thats why

parkpaul67

I’m trying to order hitch kit for my 2008 gl450 just got all parts number from getmercedesparts.com with trailer hitch & cable kit it came out close To $665 . but Do I also need to buy lower shield ? IT’S another $ 330 for the parts. Also where exactly SAM s located so I can hook up the wire . Thanks

jimmyp

I cut mine out like many others with a dremal when you take the sheild off flip it over and you will see the line where it needs to be cut, easy! Sam is in the rear right corner below fuses. If you need to know where to plug into let me know and I will look ar mine. Also when you guys drop the bumper you can leave it on the ground with the rear wires hooked up. Not a bad job but it looks like the price went down on them as I paid 950.00 from the same place in 2010.

ttlywkd

just purchased a trailer hitch from stealership..... planning to install myself coz the dealership charging me almost $ 600. But when I opened the box, no diagrams nor instructions..... any assistance (diagrams/steps/instructions) wil be greatly appreciated as I'm stuck trying to get the rear bumper out...... its 01:00 and hardly even moved the bumper..... thanks

parkpaul67

Thanks for the info Jimmyp Yea it will be much helpful if you let me know where the plug goes to. Since the cable kit don’t come with any instructions.

jimmyp

The bumper has a few 10mm nuts the one are inside wheel well behind the plastic just pull it out to get to them also the ones you have to get from inside the trunk area above the ablue tank. I will check my plugs and let you know where they go

jimmyp

power goes to red fuse spot under the red wire in the pic also rust color wire goes to ground under bolt and sam just plugs in to the only spot it can

Dynamic

I have just ordered a compete hitch from a salvage yard. One extra thing they are willing to send me is the SAM module if I can only tell them where it's located, how it looks and where it plugs into. Can someone provide me with that info please? Also, will it work if I plug it into the same make model and year or there is no way around buying a new one from the dealer and having it programmed.

jimmyp

sam is below fuse box on right rear of truck below tail light about 6x6 box. Did you check to see if you had one in your truck first?

jonathankreb

Can anyone give me the details about the electrical connections? I connected the trailer harness to the SAM, put brown to ground, and ran the red up to the fuse panel, left the green connection for a future brake controller--where do the extra relay and fuses that came with the hitch go, and where specifically does the red connect?

thanks in advance!