Need help, trailer wire harness install
01-31-2018, 05:01 PM
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2009 gl 320
Need help, trailer wire harness install
Bought a factory hitch and wire harness and currently installing. Can someone tell me where I plug the factory wire harness in at? I see that the power line hooks up to the fuse box but don't see any connection for the plug.
Thanks in advance!!!
Thanks in advance!!!
01-31-2018, 05:09 PM
#2
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Here, do this... I just tried it and it returned many threads that will help you... Go to the advanced search function, select the X164 subforum and then search for "hitch" as a "title only" search.
01-31-2018, 05:16 PM
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2009 gl 320
I've been trying that and have yet to find an exact answer. I see a blank spot in the back of the rear fuse box but it's a different size plug. Now I'm wondering if I got the wrong harness and does it plug in somewhere else?
Thanks for the help.
Thanks for the help.
01-31-2018, 05:26 PM
#4
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Mine came with it already installed and if needed, I can take a picture of something for you. Bu try this thread - it seems to have what you need?
https://mbworld.org/forums/gl-class-...nightmare.html
https://mbworld.org/forums/gl-class-...nightmare.html
01-31-2018, 05:41 PM
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2009 gl 320
From what I've been reading the wire harness changed in 2010. The rear SAM unit in 2010 was placed under the passenger seat. The rear SAM unit in my 2009 is directly under the rear fuse box and the trailer wire harness does not plug into it. There's only plug and I'm thinking it should go to the rear fuse box but I'm not sure. I've been searching for some kind of detailed installation but can't find anything.
Thanks again!!
Thanks again!!
01-31-2018, 07:14 PM
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Well, I found out it plugs into the sam unit. But the open port in the sam unit is a different size than the wire harness plug.. Wondering if I need a different sam unit???
02-08-2018, 01:16 PM
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02-08-2018, 01:39 PM
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2009 gl 320
Well, just got this sorted out today. I am still using the original trailer brake harness they gave me, and it seemed that they gave me the wrong electronic brake controller harness. Included in the electronic brake control harness is the adapter needed to go from the trailer brake harness to the SAM unit. Just kinda weird because this adapter is about 4 feet long, only needs to be a couple inches.
