Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
 


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 04-07-2018, 07:39 PM   #1
New Member
 
Currently Looking...
Currently Looking...
Atascadero , California
Join Date: Aug 2016
Posts: 3
Tow vehicle electrical problems

I recently purchased a 2010 19 ft AS International. My tow vehicle is a 2011 Mercedes GL 450. I have been unsuccessful in the installation of a Tekonsha P3 trailer brake controller. The MBZ dealer constructed a wiring harness to connect the brake controller. After about two weeks of their efforts to make it work the brake lights and the turning indicators will work when the car lights are on automatic during the daytime and the running lights for the trailer will not operate. (It appears that the brake controller is sending electrical signals to the trailer brakes.)With the lights turned on manually during the daytime, the trailer lights flash and the brake/turn indicator do not work at all. This evening I tried to operate the lights on automatic. The sensors cause the headlights to come on when it is dark. Under these conditions, none of the exterior trailer lights work at all.

The electronics in the MBZ are a nightmare and I am hoping someone has had a solution to these issues.
There are two things I don't know.
1: Are the exterior lights to the AS LED lights?
2. Is a wireless brake controller a viable option?

Any info would be greatly appreciated.

Thanks
michaelann1 is offline   Reply With Quote
Old 04-07-2018, 09:17 PM   #2
Rivet Master
 
Al and Missy's Avatar
 
2002 30' Classic S/O
Fleming Island , Florida
Join Date: Nov 2013
Posts: 4,668
It sounds like the brake controller is working and you have a problem with the rest of the trailer wiring harness. I bought a truck because my 2008 E-350 could not be set up to tow even a small trailer without spending a fortune. The story I got was that a rear body computer is different for towing due to the electronic stability control. US models were not equipped with the computer that allows towing. It could be installed for about $1000.

My best guess is that the car's computer is detecting excessive current on the taillight and turn signal lines and turning them off.

The clearance lights operate from the same line as the tail lights. Tail lights will not be on during the daytime on automatic.

Back in the day there was a thing called a trailer isolator. It connected to a 12V line and the tail, turn and brake lights. The tail, turn, and brake light signals operated a relay or solid state switch that used the 12V line to operate the trailer lights. This limited the current drawn from the vehicle light wires.

Turns out they still make them. Maybe your dealer can figure out how to wire it in.

This one for a motorcycle trailer might work, or there are probably others with higher current capabilities.

https://www.amazon.com/Rivco-Univers.../dp/B0058P2QV8

Edit - looked a little further. This may be what you need:

https://www.etrailer.com/Custom-Fit-...ins/46255.html


Al
__________________
“You cannot reason someone out of a position they have not been reasoned into"
Al, K5TAN and Missy, N4RGO WBCCI 1322
2002 Classic 30 Slideout -S/OS #004
2013 Dodge 2500 Laramie 4x4 Megacab Cummins
Al and Missy is offline   Reply With Quote
Old 04-08-2018, 06:23 AM   #3
New Member
 
Currently Looking...
Currently Looking...
Atascadero , California
Join Date: Aug 2016
Posts: 3
Thank you Al. This is very helpful and your explanation of excessive current seems quite consistent with what is happening.
michaelann1 is offline   Reply With Quote
Old 04-08-2018, 09:20 AM   #4
Rivet Master
 
Mollysdad's Avatar

 
2017 26' Flying Cloud
Tampa , Florida
Join Date: Feb 2017
Posts: 7,638
Blog Entries: 1
The Tekonsha P-3 only needs four wires. (It comes with a harness to bare ends)
1. 12v.
2. Ground.
3. Brake lights.
4. Electric brakes output to trailer.

Snaking the wires might be a pain, but the concept is simple. Maybe your MB guy is overthinking it.
It sounds like your mechanic is using the tail lights to supply 12 v. instead of a straight line to battery. (Ignition switch.)
I think mine is always on. It goes to sleep after 15 minutes so it doesn't drain the battery. Stepping on the brakes wakes it up.
Mollysdad is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
LED Tow Vehicle to LED Trailer Problems murreywalker Hitches, Couplers & Balls 28 06-11-2022 12:00 PM
Tow vehicle electrical hook up willyjay Electrical - Systems, Generators, Batteries & Solar 10 03-28-2017 06:40 PM
electrical issues > Tow Vehicle pin out not matching Trailer receptacle taddilack Electrical - Systems, Generators, Batteries & Solar 3 08-04-2014 11:21 AM
Problems Problems Problems pjzuk General Motorhome Topics 6 09-03-2007 07:25 AM
Tow vehicle electrical problem Boondocker Tow Vehicles 5 01-10-2007 07:26 AM


Featured Campgrounds

Reviews provided by

Disclaimer:

This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.



All times are GMT -6. The time now is 10:10 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.