Install factory wiring harness for trailer lights
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Joined: Oct 2018
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GL 450
Install factory wiring harness for trailer lights
Hey guys! I was wondering if anyone has installed the factory wiring harness for the trailer lights on a GL450? I installed a trailer hitch receiver and have the factory harness from the dealership, but cannot find any info on how to attach it to the fuse box in the rear of the vehicle. Has anyone done this before? If so, could you explain it so it's done correctly? Thanks!
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Joined: Sep 2005
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From: Albuquerque
'10 CL550, '12 GL550
It doesn’t attach to the fuse box, but rather to the rear SAM (signal acquisition module) which resides underneath the subwoofer. This is a box of electronics to which lots of things connect, taillights, rear fold out windows, etc.
For the early X164 at least, if your vehicle didn’t come from the factory with trailer hitch installed, subsequent retrofit required replacing the existing SAM with one ready for trailer connection.
Perhaps tomorrow I’ll remember to look at documents on my desktop to post if relevant ... not tonight from ipad.
Meanwhile a good idea to search previous posts here for additional information. A related topic is whether you want electric trailer brake control, which is possible via your factory harness, but may require wiring to the front if yours is a really early model.
For the early X164 at least, if your vehicle didn’t come from the factory with trailer hitch installed, subsequent retrofit required replacing the existing SAM with one ready for trailer connection.
Perhaps tomorrow I’ll remember to look at documents on my desktop to post if relevant ... not tonight from ipad.
Meanwhile a good idea to search previous posts here for additional information. A related topic is whether you want electric trailer brake control, which is possible via your factory harness, but may require wiring to the front if yours is a really early model.
