Power at 7 pin hitch wiring
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 32
Likes: 10
2016 GLE 350
Power at 7 pin hitch wiring
Hi,
New MB GLE 350 4Matic owner here.
I bought 2016 model with under 30K miles and CPO warranty (in total 18 months).
The car has factory hitch (option code 550)
I specifically bough this car so I can tow the Lance trailer I purchased (That also 2016).
Trailer is rated 4100 lbs dry and hitch weight of 435 lb. GVWR is 5500 lbs (Way below 7200 for GLE).
Trailer has the "equalizer" stabilizing hitch.
I am driving 1400 miles next week to pick up the trailer.
I purchased Curt Echo Mobile Break control (it simply plugs at the 7 pin connector at the back of car).
Echo connects to your phone via bluetooth but it needs power.
When I got the car home and plugged in the Echo no power. I called their customer service and he walked me through
measuring voltage and it reads '0' between pin 1 PM and 7PM position.
I read somewhere that MB turns off the power.
1) Is this something I can turn on some option in the car?
2) I read that you have to plug in the actual trailer 7 pin plug into car for it to enable power, is this true?
I can take to local MB dealer but I am afraid I may not get it resolved in time. (I have 3 days before travel).
I did not go through plugging in the controller at front of the car option because the connector for MB can not be shipped in time.
If anyone knows of a procedure on turning on the power, I will appreciate step by step instruction.
Thank you,
Robert
New MB GLE 350 4Matic owner here.
I bought 2016 model with under 30K miles and CPO warranty (in total 18 months).
The car has factory hitch (option code 550)
I specifically bough this car so I can tow the Lance trailer I purchased (That also 2016).
Trailer is rated 4100 lbs dry and hitch weight of 435 lb. GVWR is 5500 lbs (Way below 7200 for GLE).
Trailer has the "equalizer" stabilizing hitch.
I am driving 1400 miles next week to pick up the trailer.
I purchased Curt Echo Mobile Break control (it simply plugs at the 7 pin connector at the back of car).
Echo connects to your phone via bluetooth but it needs power.
When I got the car home and plugged in the Echo no power. I called their customer service and he walked me through
measuring voltage and it reads '0' between pin 1 PM and 7PM position.
I read somewhere that MB turns off the power.
1) Is this something I can turn on some option in the car?
2) I read that you have to plug in the actual trailer 7 pin plug into car for it to enable power, is this true?
I can take to local MB dealer but I am afraid I may not get it resolved in time. (I have 3 days before travel).
I did not go through plugging in the controller at front of the car option because the connector for MB can not be shipped in time.
If anyone knows of a procedure on turning on the power, I will appreciate step by step instruction.
Thank you,
Robert
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 32
Likes: 10
2016 GLE 350
I found the answer...
I took the car to RV dealer and they hooked up RV 7 pin simulator.
That did the trick.
When we hooked up simulator directly to car, I was able to verify right, left signal and breaks.
Next I plugged in my Echo controller in the car and sure enough power is supplied.
I was able to connect to Echo using blue tooth and verify functions.
All I have to do is hook up trailer once when I pick up the trailer and then plug in the Echo break controller.
I took the car to RV dealer and they hooked up RV 7 pin simulator.
That did the trick.
When we hooked up simulator directly to car, I was able to verify right, left signal and breaks.
Next I plugged in my Echo controller in the car and sure enough power is supplied.
I was able to connect to Echo using blue tooth and verify functions.
All I have to do is hook up trailer once when I pick up the trailer and then plug in the Echo break controller.
Newbie
Joined: Aug 2020
Posts: 3
Likes: 0
GLS 450
Do you know if the factory tow hitch 7 pin connector is 12v? We are also using the curt echo for our 2017 GLS 450 and in checking if we are indeed getting electrical signal from our factory tow hitch realized that we can’t test the curt without a trailer attached. We don’t own a trailer and have some airstream rental planned until more come out for purchase.
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 32
Likes: 10
2016 GLE 350
Do you know if the factory tow hitch 7 pin connector is 12v? We are also using the curt echo for our 2017 GLS 450 and in checking if we are indeed getting electrical signal from our factory tow hitch realized that we can’t test the curt without a trailer attached. We don’t own a trailer and have some airstream rental planned until more come out for purchase.
The problem with power is on MB hitch side.
The car checks presence of actual trailer connection BEFORE turning on the power.
One way to fool the system is to connect the trailer wiring tester/simulator (I too my MB and Curt Echo to local RV dealer).
Once the power is on at the hitch wiring you will see led turn on at Curt Echo.
BTW: I ended up returning Curt Echo because of power issues. Instead I installed permanent break controller at the front of car (relatively easy to do, see my other thread).
Good luck.
Other thread...
https://mbworld.org/forums/gle-class...onnection.html
Last edited by Roberttz; Aug 11, 2020 at 06:18 AM.
Senior Member
Joined: Feb 2019
Posts: 262
Likes: 69
From: Wisconsin
2016 GLE 350 4Matic, 2019 GLS 450 4Matic
Yes it's 12V.
The problem with power is on MB hitch side.
The car checks presence of actual trailer connection BEFORE turning on the power.
One way to fool the system is to connect the trailer wiring tester/simulator (I too my MB and Curt Echo to local RV dealer).
Once the power is on at the hitch wiring you will see led turn on at Curt Echo.
BTW: I ended up returning Curt Echo because of power issues. Instead I installed permanent break controller at the front of car (relatively easy to do, see my other thread).
Good luck.
Other thread...
https://mbworld.org/forums/gle-class...onnection.html
The problem with power is on MB hitch side.
The car checks presence of actual trailer connection BEFORE turning on the power.
One way to fool the system is to connect the trailer wiring tester/simulator (I too my MB and Curt Echo to local RV dealer).
Once the power is on at the hitch wiring you will see led turn on at Curt Echo.
BTW: I ended up returning Curt Echo because of power issues. Instead I installed permanent break controller at the front of car (relatively easy to do, see my other thread).
Good luck.
Other thread...
https://mbworld.org/forums/gle-class...onnection.html
Our camper uses a pre-wired observation camera tied into the running light circuit, for example, that doesn't work presently due to the CANBUS not supplying constant voltage- the 12 volt pin is constant though. An adapter from Furrion to get camper running lights supplied with constant voltage is new and gets the vehicle to supply constant voltage and was brought about by not only imports using the new technology, but also 2019 American pickups.
Thread Starter
Junior Member
Joined: Jun 2020
Posts: 32
Likes: 10
2016 GLE 350
Interesting about the tester you said your dealer used. My initial problem with my factory installed hitch on my 2016 GLE350 was the connectors in the back right rear of the car were not connected together and since nobody had towed with the car before it was never discovered. My dealer told me that modern testers don't work with the CANBUS system and that they had to make an old-school tester to determine if the 7-pin connector works properly. I have oscilloscope printouts showing the modulated power supplied and why the current LED light 7-pin testers, like Tekonsha, don't work with even Tekonsha electric brake controllers.
Our camper uses a pre-wired observation camera tied into the running light circuit, for example, that doesn't work presently due to the CANBUS not supplying constant voltage- the 12 volt pin is constant though. An adapter from Furrion to get camper running lights supplied with constant voltage is new and gets the vehicle to supply constant voltage and was brought about by not only imports using the new technology, but also 2019 American pickups.
Our camper uses a pre-wired observation camera tied into the running light circuit, for example, that doesn't work presently due to the CANBUS not supplying constant voltage- the 12 volt pin is constant though. An adapter from Furrion to get camper running lights supplied with constant voltage is new and gets the vehicle to supply constant voltage and was brought about by not only imports using the new technology, but also 2019 American pickups.
Not sure what type of tester it was but it worked.
I recently installed the observation camera on my camper and tapped into running lights.
It works just fine.
Mind you I never had problems with MB not supplying running lights or signal lights (it was only the 12V supply pin not working).
Newbie
Joined: Aug 2020
Posts: 3
Likes: 0
GLS 450
We ended up testing our 7 pin on our 2017 GLS 450 with a friend's trailer. It all hooked up and turned on and we could hear the brakes turn on on the trailer when using the ECHO. Our first trip is next week....hoping for the best.
