AI Electrical Issue Using Trailer Plug

[Doug Odom]

I'm sorry if this is a duplicate but I cannot find my original post. Pilot error no doubt. Anyway, I have a 2014 and a half airstream interstate. I recently purchased a Stowaway 2 cargo carrier that attaches via the AI's receiver hitch.
The unit comes with an adapter that utilizes the airstream seven pin round trailer module and then connects to the stowaways four pin module. The stowaway unit has running lights, turn signals lights, brake lights and lcense plate light capabilities.
Everything on the stowaway unit and the AI operate correctly when connected with the ignition switch on but the engine not running. As soon as the engine is started and the brake pedal is applied it deactivates the blind spot assist feature on the AI. If the four pin module connected to the stowaway is unplugged the AI blind spot assist returns to its normal function.
I had an RV service center take a look at the problem. They said that the four pin adapter is correct but they offer no solution . They just said that Mercedes-Benz wiring system is a different animal than they normally deal with.
Any suggestions would be appreciated. Thanks for listening.

[73shark]

I remember reading that the MB's computer monitors the load on each circuit which makes it difficult to replace incandescent bulbs w/ LEDs. Could be that the Stowaway 2 is confusing the computer.

[Harleydeal]

I have the same problem on my 2016. I believe the problem is probably the box obstructing the sensors in the rear bumper.

[Nuvite-F]

Originally Posted by Doug Odom

Everything on the stowaway unit and the AI operate correctly when connected with the ignition switch on but the engine not running. As soon as the engine is started and the brake pedal is applied it deactivates the blind spot assist feature on the AI. If the four pin module connected to the stowaway is unplugged the AI blind spot assist returns to its normal function.

I suspect that what is happening is that the blind spot assist system checks for a load on the trailer light lines and then turns itself off if a trailer is detected. (It thinks the stowaway is a trailer.) You might see if you can find something about it in the owners manual, or talk to a Mercedes dealer.

[bsedor]

Originally Posted by Doug Odom

I'm sorry if this is a duplicate but I cannot find my original post. Pilot error no doubt. Anyway, I have a 2014 and a half airstream interstate. I recently purchased a Stowaway 2 cargo carrier that attaches via the AI's receiver hitch.
The unit comes with an adapter that utilizes the airstream seven pin round trailer module and then connects to the stowaways four pin module. The stowaway unit has running lights, turn signals lights, brake lights and lcense plate light capabilities.
Everything on the stowaway unit and the AI operate correctly when connected with the ignition switch on but the engine not running. As soon as the engine is started and the brake pedal is applied it deactivates the blind spot assist feature on the AI. If the four pin module connected to the stowaway is unplugged the AI blind spot assist returns to its normal function.
I had an RV service center take a look at the problem. They said that the four pin adapter is correct but they offer no solution . They just said that Mercedes-Benz wiring system is a different animal than they normally deal with.
Any suggestions would be appreciated. Thanks for listening.

In the manual it says the blind spot monitor is disconnected when you plug in a trailer (or even just the adapter).

[Tomzstream]

That is correct. MB detects the electrical connection and disables the Blind Spot detection (the triangular mirror lights remain amber). This is intentional as it cannot be relied upon to function correctly if there is any sort of obstruction. I ran into this when test driving a Roadtrek Agile which uses a continental spare tire kit that also connected to the trailer socket. The dealership did not have a clue why. RT later redesigned the kit to hardwire into the electrical system rather than using a plug. You might try to do the same... The BLIS functions on cameras and to a lesser extent sensors, so you might still be able to use your box.

[Farmer Dan]

Doug
Does the Stowaway have LEDs on it? When I ordered mine the sales lady advised not to get LEDs because Mercedes Benz electrical system can react strangely to them.
Maybe a solution would be as simple as changing bulbs - if you are lucky!!!
Dan

[Doug Odom]

Thanks for all of the good information. You are correct that the MB treats the stowaway as a trailer . MB rightly causes the blind lane assist to be deactivated when a trailer or similar item is attached as the system becomes unreliable because of sensor interference. It is mentioned in the manual as noted under trailer towing. I was looking for an electrical problem and not considering it to be a design protection issue. Thanks again.