LED Tow Vehicle to LED Trailer Problems

[Wsmith]

Originally Posted by murreywalker

I talked with them and they suggested the incandescent method.

The harness is located under the bed and splicing in sockets to hold bayonet style bulbs in three wires would be a solution to the issue.

What I don't understand is, why didn't Airstream address this issue when they knew it (I talked with them earlier this morning, and they acknowledged it was an issue)?

Just a reminder that a incandescent light bulb without protection can be a fire hazard. I knocked leans off my storage compartment light with a water hose while getting my wheel ramps out and the bulb melted a water hose in about 10 minutes.

It would be cheaper to go to Radio Shack and getting some resistors to put in-line.

[murreywalker]

Originally Posted by lewster

You might want to check out the load resistors available here: Load Resistor Kits

I like the idea of a load resistor kit, but haven't the foggiest idea of how or where to install in my trailer/vehicle.

Thoughts or suggestions would be most welcomed.

Thanks!

[lewster]

Originally Posted by murreywalker

I like the idea of a load resistor kit, but haven't the foggiest idea of how or where to install in my trailer/vehicle.

Thoughts or suggestions would be most welcomed.

Thanks!

They generally install in-line with the tail/turn lights at the rear of the trailer or vehicle being towed......inside the tail light assembly if there is sufficient space.

[SteveandJo]

Hi All, it's 6/18/2012 and I would like some follow-up on your discussion.
Murreywalker mentioned that etrailer.com had a 7-pin adaptor on backorder in May 2011. I've just done a simple search and browse and they've got a 7-pin to 7-pin adaptor on special price under $25. Do you know the model that was referred to last year?

We have a 2008 MB GL550 that we want to attach to a new 2012 25FB Flying Cloud. Didn't know the LED to suv issue until after we purchased and the RV rep hooked up the suv and said, "Guess what..." Came across your discussion and it's been very consoling to know we're not alone with this. I agree with all comments and intend to write to Airstream and Mercedes to let them know the problem STILL exists and isn't new... It seems that the two world-class manufacturers could make some money on an elegant package they could sell us now and in the future.

[ddruker]

I posted the information below on a less popular LED trailer thread by accident - will repost here since more people are likely to be following this thread.

The net is the problem is entirely with the tow vehicle, and not with the airstream.

I just upgraded my Safari to LED taillights and ran into the same problem with my Mercedes GL 350. Pretty frustrating for a TV that has LED lighting to not know how to talk to a trailer that also has LED lighting.

The symptoms: Things are fine during the day, but whenever the headlights go on, all of the running lights and the tail lights on the trailer flash rapidly. The brake lights do come on and stay on when pressing the brake pedal.

I spoke with a factory tech as my local dealer is clueless in all things towing related. The problem is that up to and through the 2012 model year, the Mercedes GL computer simply doesn't know about LED trailer lights. They know about the problem and acknowledge it and have a workaround as I'll describe below.

What is going on is when the truck senses the trailer umbilical is plugged in, and then when the headlights go on, it sends a series of diagnostic pulses to make sure the trailer tail lights are ok. It is expecting to see the resistance profile of incandescent bulbs only in the tail light circuit.

Since the LED bulbs look very different electrically, the computer thinks that there is a fault in the trailer's tail light / brake light system.

And to make sure you know about it, the GL rapidly and continuously flashes all of the trailer lamps - the running lamps, the tail lamps, etc - and even the collision avoidance triangles in the GL mirrors, as a warning that something is wrong.

According to MB USA, the fix is to install two 220 Ohm, minimum 1.5 Watt resistor - one each in parallel with both the left turn/stop and right turn stop circuits. You can do this anywhere in the circuit - using an adapter at the trailer plug, in your taillight fixtures, or anywhere in between. Mercedes actually makes an trailer plug adapter - but only for four and five pin trailers - and get this - they want to charge more than $200 for it. For what nets out to two 75 cent resistors.

They say this will be fixed in the 2013 model year and the new generation GL will understand LED trailer lights.

Attached is PDF Mercedes sends out on this... Pretty obviously hacked together by somebody here as opposed to a formal data sheet out of Germany.

All of this (and their silence on weight distribution, and their wimpy tongue weight specs) together do not give a ton of confidence the Germans are spending time to really understand the towing market here in the USA, beyond marketing that their vehicles have a 7,500 pound towing capacity.

[murreywalker]

I have completely forgotten about this thread. My bad!!!!!

VW sells a short (about 3 feet) cable that attaches to the trailer's, which in turn will plug into your tug's 7 pin connector. It costs (give or take) $40.00. This takes care of the problem.

AND the 2013 GLs will have the problem solved with a built in resistance.

[gtdowning]

no wisdom to add - just disappointment. I'm having the same problem with my 2011 MZB SUV... in picking up my brand new Flying Cloud 23FB. The AS tech could do nothing, and I am so disappointed I could not take home my new FC! I don't expect AS to wire in anything non standard in their trailers - so looking for another solution. Per the suggestion above, I am reaching out to Andrew T. from Can-Am RV for an adapter

[jcl]

Originally Posted by gtdowning

no wisdom to add - just disappointment. I'm having the same problem with my 2011 MZB SUV... in picking up my brand new Flying Cloud 23FB. The AS tech could do nothing, and I am so disappointed I could not take home my new FC! I don't expect AS to wire in anything non standard in their trailers - so looking for another solution. Per the suggestion above, I am reaching out to Andrew T. from Can-Am RV for an adapter

It isn’t an Airstream issue, and it has nothing to do with the turn signal flasher as some suggest. Your vehicle computer senses when a bulb is out and the trailer LED bulbs don’t use sufficient current for the sensor.

The solution, unless you want to modify the trailer wiring with resistors, is a simple plug in adapter. E trailer sells them. Mine came from the local U Haul store.

Something like this.

https://www.etrailer.com/Trailer-Wir...ady/20142.html

Another option is discussed here

https://www.etrailer.com/question-616833.html

[gator.bigfoot]

I had the same issues with ML. Added regular bulbs to the trailer connection box at the front of the trailer and the problem was solved. This is what Andy suggests. There are other posts on the subject as well as wiring diagrams. It's a very simple mod since as others have mentioned it is a loading issue for the sense circuit on the MB.