Wire routing from rear SAM to driver side dash for trailer
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2010 ML350
Wire routing from rear SAM to driver side dash for trailer
2010 ML350 w/o trailer hitch option.
Hi. I'm adding an OEM trailer hitch, probably would have been better to sell the vehicle and buy one with it, but it's a little late for that. Anywho, I've added the trailer hitch and ran the wire harness up to the rear SAM. Next is getting the 4 wire green plug from the wire harness up under the drivers side dash for the electric brake control. I'm seeing two ways to do it.
1). Either run up the center of the vehicle under the center console
2). Run it across under the rear seat and then up along the left side of the car
I've had the center console out and removed the front and rear floor trim plates from the passenger and drivers side. I'm not seeing a good path through using either method. I'll probably end up removing the connector so I can run the bare wires and don't have to push the housing with them.
I'm curious if anyone has given this wire routing a try and have a recommendation/suggestions on how to do either one. This is the last thing I need to do before have the dealer replace the rear SAM and reprogram the new one I bought that supports the trailer option.
Thank you!
Hi. I'm adding an OEM trailer hitch, probably would have been better to sell the vehicle and buy one with it, but it's a little late for that. Anywho, I've added the trailer hitch and ran the wire harness up to the rear SAM. Next is getting the 4 wire green plug from the wire harness up under the drivers side dash for the electric brake control. I'm seeing two ways to do it.
1). Either run up the center of the vehicle under the center console
2). Run it across under the rear seat and then up along the left side of the car
I've had the center console out and removed the front and rear floor trim plates from the passenger and drivers side. I'm not seeing a good path through using either method. I'll probably end up removing the connector so I can run the bare wires and don't have to push the housing with them.
I'm curious if anyone has given this wire routing a try and have a recommendation/suggestions on how to do either one. This is the last thing I need to do before have the dealer replace the rear SAM and reprogram the new one I bought that supports the trailer option.
Thank you!
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From: Colorado
G550
You can save a lot of effort using a wireless controller, available from either Curt or Tekonsha. These plug into your vehicle's trailer connector and link to your smartphone via Bluetooth. No dash mounted controller unit is required.
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2010 ML350
Thanks for the suggestion, I didn't know this existed. Looks like I have to sell the Tekonsha P3, I bought.
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2010 ML350
Thanks. Relative you your ML, if they sold the vehicle with a hitch, then you should be able to do it with OEM parts, but will probablyrequire SAM upgrade and wire harness upgrade. The other option is to use an aftermarket. The reason I went with OEM, was because it was a better hitch design than the aftermarket hitches I looked at. I had to get the hitch from a recycler as it had been discontinued. There are some good write ups on the ML350 process, but not for the faint of heart and involves the dealer for SAM reprogramming.
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From: Albuquerque
'10 CL550, '12 GL550
At some point Mercedes began including the wiring as standard, providing a green connector above driver's feet under the panel. Not sure whether this was all or just those with hitch standard.
I've retrofitted two early 2007 GL that did not have the wiring, The part number for the factory wiring harness for trailer controller is 164 540 69 13
Mercedes expectation is that you run the wiring through the rear SAM so it can be included with the original equipment 7-pin connector. The part number above plugs into the rear SAM.
I'd highly recommend the original equipment 7-pin wiring that connects to the rear SAM, as as this gives you dashboard messages as regards trailer bulbs. Also, if yours has Airmatic it will not permit the usual highway speed vehicle lowering when a trailer is detected. This is a CANbus electrical and you DO NOT want to "tap into" wiring to get trailer lights.
On 2007 GL if car wasn't factory equipped with hitch, a new SAM was required. I think by 2010 not. I'd search this forum for previous threads on this. Pretty sure the GL forum has the official Mercedes instructions attached to a post and they could very likely be here too.
I've retrofitted two early 2007 GL that did not have the wiring, The part number for the factory wiring harness for trailer controller is 164 540 69 13
Mercedes expectation is that you run the wiring through the rear SAM so it can be included with the original equipment 7-pin connector. The part number above plugs into the rear SAM.
I'd highly recommend the original equipment 7-pin wiring that connects to the rear SAM, as as this gives you dashboard messages as regards trailer bulbs. Also, if yours has Airmatic it will not permit the usual highway speed vehicle lowering when a trailer is detected. This is a CANbus electrical and you DO NOT want to "tap into" wiring to get trailer lights.
On 2007 GL if car wasn't factory equipped with hitch, a new SAM was required. I think by 2010 not. I'd search this forum for previous threads on this. Pretty sure the GL forum has the official Mercedes instructions attached to a post and they could very likely be here too.
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2010 ML350
My 2010 doesn't have the green connector under the dash, so I think 2011 was when life got a lot easier. The green connector is part of the new harness I had to buy to support the OEM trailer hitch, hence the question about running from rear SAM to under the dash. I think I'm going to go with the Teknosha brake controller that can be mounted on the trailer. I need a brake controller anyways so, doing solves for routing the wire challenge. I also needed a new rear SAM for my 2010 as the connector on the new wire harness doesn't have a place to plug into with the old SAM. The last piece is getting the dealer to program the new SAM.
Any thoughts on what happens if you just disconnect the rear SAM for a short trip to the dealer to reprogram the new SAM. I'm guessing lot of errors, but I don't see why the engine wouldn't run. You can swap the two in a couple of minutes, but the dealer will probably charge 1 hr labor for this simple task.
Any thoughts on what happens if you just disconnect the rear SAM for a short trip to the dealer to reprogram the new SAM. I'm guessing lot of errors, but I don't see why the engine wouldn't run. You can swap the two in a couple of minutes, but the dealer will probably charge 1 hr labor for this simple task.
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2010 ML350
I could certainly do that, but then they would probably try to diagnose all the errors. I'll ask the service guy about doing that. Thanks.
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Tekonsha Wireless Controller
2. Do you know the fuse location for the brake control circuit?
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G550
I have the Curt Echo wireless controller - no problem pairing with my Android phone. Pairing two components? Do you mean your controller and phone? Not sure where your fuse might be. Buy a Curt 7-way tester (~$20) - can save you time ensuring your car's circuits are working.
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Thanks for getting back to me. I was a little vague with my question. The zTekonsha brake controller has a trailer-mounted unit controlled by a Bluetooth controller in the car. They must be paired to operate. For some reason the earlier model doesnt play well with European vehicles.
I have watched three YouTube videos on the Curt, and have decided that it looks like a better choice. The only potential problem is, because of the awkward positioning of the 7 pin outlet up under the bumper on my car, if the Curt will hang down too far as it will be pointing toward the ground when plugged in.
thanks also for tip on the circuit tester.
I have watched three YouTube videos on the Curt, and have decided that it looks like a better choice. The only potential problem is, because of the awkward positioning of the 7 pin outlet up under the bumper on my car, if the Curt will hang down too far as it will be pointing toward the ground when plugged in.
thanks also for tip on the circuit tester.
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From: Colorado
G550
Thanks for getting back to me. I was a little vague with my question. The zTekonsha brake controller has a trailer-mounted unit controlled by a Bluetooth controller in the car. They must be paired to operate. For some reason the earlier model doesnt play well with European vehicles.
I have watched three YouTube videos on the Curt, and have decided that it looks like a better choice. The only potential problem is, because of the awkward positioning of the 7 pin outlet up under the bumper on my car, if the Curt will hang down too far as it will be pointing toward the ground when plugged in.
thanks also for tip on the circuit tester.
I have watched three YouTube videos on the Curt, and have decided that it looks like a better choice. The only potential problem is, because of the awkward positioning of the 7 pin outlet up under the bumper on my car, if the Curt will hang down too far as it will be pointing toward the ground when plugged in.
thanks also for tip on the circuit tester.
As you probably know, the newer cars with all the collision and blind spot sensors disable the associated systems when a trailer is connected by sensing the trailer's light circuits. This prevents the trailer from false triggering the sensors. The 7-way connector circuits are disabled until an adequate load is sensed (about 20 mA, I think). In the absence of an adequate load being sensed, the 12 volt circuit to the 7-way connector is disconnected. I assume your Tekonsha controller was getting 12 volt power from the 7-way, so its Bluetooth was powered?
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All that makes perfect sense. But the Tekonsha would not pair even with the trailer completely connected to the car. It does explain why I couldnt get any readings at the car’s plug when there was no hitch in the receiver.
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From: Colorado
G550
Yes, that seems unusual. The trailer light wiring should pass directly through the controller, so that the lights then activate the 12 volts to the controller's Bluetooth.
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This has continues to be a problem. I borrowed a Curt unit, and also could not make it work with my GLE. Neither the Tekonsha nor the Curt seem to be getting power from the seven pon factory plug. Strangely, I do show power at the factory plug when neither are connected.
The power/pairing light on the Curt does not light when plugged in and the Tekonsha gives a “no connection “ error code after trying to pair.
Both units do pass the lighting signals through to the trailer, though.
The power/pairing light on the Curt does not light when plugged in and the Tekonsha gives a “no connection “ error code after trying to pair.
Both units do pass the lighting signals through to the trailer, though.
MBWorld Fanatic!
Joined: Oct 2019
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From: Colorado
G550
This has continues to be a problem. I borrowed a Curt unit, and also could not make it work with my GLE. Neither the Tekonsha nor the Curt seem to be getting power from the seven pon factory plug. Strangely, I do show power at the factory plug when neither are connected.
The power/pairing light on the Curt does not light when plugged in and the Tekonsha gives a “no connection “ error code after trying to pair.
Both units do pass the lighting signals through to the trailer, though.
The power/pairing light on the Curt does not light when plugged in and the Tekonsha gives a “no connection “ error code after trying to pair.
Both units do pass the lighting signals through to the trailer, though.
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From: San Francisco Bay Area
2006 R500
This has continues to be a problem. I borrowed a Curt unit, and also could not make it work with my GLE. Neither the Tekonsha nor the Curt seem to be getting power from the seven pon factory plug. Strangely, I do show power at the factory plug when neither are connected.
The power/pairing light on the Curt does not light when plugged in and the Tekonsha gives a “no connection “ error code after trying to pair.
Both units do pass the lighting signals through to the trailer, though.
The power/pairing light on the Curt does not light when plugged in and the Tekonsha gives a “no connection “ error code after trying to pair.
Both units do pass the lighting signals through to the trailer, though.
MBWorld Fanatic!
Joined: Oct 2019
Posts: 5,156
Likes: 1,770
From: Colorado
G550
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From: Albuquerque
'10 CL550, '12 GL550
Basically testers won’t work from the 7-pin connector as original on your Mercedes.
its a CAN bus electrical system and apparently it doesn’t send power to the plug until it detects there is a trailer connected. Apparently a tester isn’t the same thing
its a CAN bus electrical system and apparently it doesn’t send power to the plug until it detects there is a trailer connected. Apparently a tester isn’t the same thing
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From: San Francisco Bay Area
2006 R500
It worked for me when used in conjunction with the Curt LED adapter plug. I think there needs to be enough resistance on one of the circuits, not sure which one.
