GL450 trailer hitch installation
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Joined: May 2007
Posts: 2,244
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From: Scottsdale, AZ
2004 RX330, 2008 Scion xB, 2001 Honda Insight Hybrid, 2010 Toyot Prius v ATP
I'd recommend doing the SAM anyway. You might use it for "real" towing one day, or perhaps the next owner would.
Senior Member
Joined: Feb 2005
Posts: 269
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From: Denver,CO
'03 CL500,& '18 GLS63. Gone: '83 500SEC,'99 500SL,'07GL450
MY MB dealer installed a hitch on my 2007 GL450 last year. 6 hrs. of labor.
Remove spare wheel and trim of spare wheel well. Remove bumper.Remove right hand ventilation. Attach rear SAM unit. Attach SAM bracket. Bolt on stiffening arms. Attach hitch. Attach wiring harness. Attach bumper. A new SAM unit may have to be installed and programmed.
Remove spare wheel and trim of spare wheel well. Remove bumper.Remove right hand ventilation. Attach rear SAM unit. Attach SAM bracket. Bolt on stiffening arms. Attach hitch. Attach wiring harness. Attach bumper. A new SAM unit may have to be installed and programmed.
Senior Member
Joined: Jul 2007
Posts: 283
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From: Maryland
S 550, S65 Coupe
I installed a factory hitch a few months ago. It was not to bad at all. The directions from MB are terrible though. The hardest part is removing the bumper cover and finding all the bolts that hold it on. The hitch itself has 4 bolts per side. The stiffening arms have 2 or 3 per side. If you got the hitch from a salvage yard make sure they gave you the strenghtening arms as well. They attach to the hitch where it mounts to the frame and slide into the frame of the truck. They are bolted to the frame through the spare tire well. PM me and I can send you the direction from MB. They are very short on words but enough pictures to figure it out. You will have to cut the lower bumper cover but it has a line inside that shows you where to cut it.
Member
Joined: Sep 2008
Posts: 222
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'13 CLS550, '17 Q7, '11 G550
Jim Ma - Did you install a new SAM module? or did you just do the hardware as well? I'm interested in putting on a hitch just to carry bikes around also, but at the prices at the dealer, it seems ridiculous - but I guess if I could find that hardware at a salvage yard and then put it on myself, that seems more reasonable without the electronics!
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Senior Member
Joined: Jul 2007
Posts: 283
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From: Maryland
S 550, S65 Coupe
I did put in a new SAM as I use mine to tow a boat. The hitch was only $603 from MB of Annapolis and the SAM was $277. I bought them online but picked them up to save the shipping cost since they are close by anyway. I had to take it to the dealer to get the SAM programmed though.
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Junior Member
Joined: Sep 2007
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BMW
I did put in a new SAM as I use mine to tow a boat. The hitch was only $603 from MB of Annapolis and the SAM was $277. I bought them online but picked them up to save the shipping cost since they are close by anyway. I had to take it to the dealer to get the SAM programmed though.
Thread Starter
Newbie
Joined: Aug 2010
Posts: 5
Likes: 0
GL450
Jim Ma, would you mind sending me the instructions along with the diagrams? This would be very helpful. I did not get the stiffening arms sent to me so I am checking to see if still available, Thanks again.
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Joined: Sep 2007
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BMW
Member
Joined: Jul 2007
Posts: 84
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From: Alta Loma, CA
S55 AMG
reviving this thread....where did you guys get the hitch from a salvage yard??
The Stealer quoted me $1400 for the hitch and $500 for install.....yikes!
I have a 2008 GL 450....any other options?
The Stealer quoted me $1400 for the hitch and $500 for install.....yikes!
I have a 2008 GL 450....any other options?
Newbie
Joined: Feb 2011
Posts: 2
Likes: 0
2008 GL450
Sam unit
I just got a factory hitch that I ordered from Ebay. It has the harness and every thing. I keep reading about this Sam unit but can't get any real info. My vehicle is 2008 GL450 and it seems to have a SAM unit already installed. Is there a different unit that I need or just get this one turned on by the dealer for the trailer harness. I haven't pulled the car apart yet to install the hitch but I can feel the unit under the amp. I just hate the idea of ripping this apart to find I need a different unit. Or what about just hooking it up the good old fashion way. Splicing right in to the tail light harness. I've done it with 3 different BMW's without throwing any codes. I don't under stand the need to wire into the SAM unit. Any input would be great. Thanks
Last edited by wygantmb; Feb 12, 2011 at 05:41 PM.
Super Member
Joined: Feb 2009
Posts: 711
Likes: 11
From: NW corner of CONUS
2008 GL 320 CDI, 2004 VW V10 Touareg TDI
The SAM unit on your '08 450 MAY not need to be changed when the hitch wiring is added. The purpose of getting the car's electronics to 'know' when you are towing is to adjust the settings of the Electronic Stability Program so as to NOT create an unsafe braking situation. Only the SAM can do that. Ask your dealer to find out for you if your SAM will need to be changed - or maybe just reprogrammed. '07s needed to be changed, late '08s did not.
The ESP is supposed to control some stability situations by applying the trailer brakes first. If it doesn't recognize there is a trailer, it can't do that. Be careful what you do, it is possible to create an unsafe situation and not even know you did.
The ESP is supposed to control some stability situations by applying the trailer brakes first. If it doesn't recognize there is a trailer, it can't do that. Be careful what you do, it is possible to create an unsafe situation and not even know you did.
Senior Member
Joined: Aug 2003
Posts: 288
Likes: 2
On the 2010 model the rear sam will have two plugs in the rear corner for the hitch if they are there you should be good. I plugged mine in and set the other plugs up and plugged in a hitch and try to raise the shocks if it works you need a program, if it tells you that it can not be raised you are good.
Newbie
Joined: Feb 2011
Posts: 2
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2008 GL450
Just as a follow up. I got the hitch installed and the SAM hooked up. It was a lot easier then I expected. Took about 2 hours and I did have to cut the lower apron just a little but it is marketed where it needs to be cut which was nice. I took the truck over the the dealer and then programed it for me, took about 1 hour (including there free wash). Cost me $99. I drove it home and right away hooked up the trailer. The lights work perfect. I did take any picture of the install because it was dark and cold out side when i did it, but it was really simple once I found all the bolts that hold it on. If anyone needs help figuring it out let me know.. Thanks for the input from everyone.
