Tow Bar Electrics

[l5foye]

I have to fit a towbar to the ML (W164) and I see I can either use a universal fitting kit for the electrics or a vehicle specific one. My local towbar fitter does not think the vehicle specific one is worth the money. He says he has been using the universal kits for some time and has never had any trouble. What would I gain by using the vehicle specific one?

 

[Spinal]

The generic one will be set up as a "bypass" - that is to say, you car will have no idea that it's towing.

A vehicle specific one will allow the ECU to know that it's towing; and adjust certain bits. Commonly, more modern cars will adjust the following (pinched from another site):
Brake electronics
Suspension system (ASS)
Engine electronics
Engine cooling system
Cruise control
Parking aids
Reversing camera
Lane change assistant
M.

 

[Bobby Dazzler]

Personally I'd go for the vehicle specific kit.

If you buy the towbar kit from a dealer it's surprisingly affordable. Best get it fitted by a specialist though.

Take a look a my thread for more information:

http://www.mbclub.co.uk/forums/electronics/138411-retrofit-towbar-w164-ml63-amg.html

 

[BTB 500]

OEM kit should also do stuff like suppressing the vehicle's reversing lights and/or rear fog lights when hitched up (since they would otherwise just illuminate the front of whatever you're towing).

 

[Dieselman]

OEM kit should also do stuff like suppressing the vehicle's reversing lights and/or rear fog lights when hitched up (since they would otherwise just illuminate the front of whatever you're towing).

A 7 way relay would stop that anyway, if wired properly.

 

[Merc Owner 2B]

I'd also like to add that vehicle specific kits require coding to the car. Dealers use STAR but some pro fitters have generic kit to do it.

If I were pulling a caravan or large trailer I'd go vehicle specific.

If you're only fitting a tow bar mounted bike carrier then the simple generic wiring kits would suffice.

 

[jackmc123]

i would advise a SMART 7 bypass Basically a 7 way relay designed for introduction to canbus systems as 3rd party hardware i would consider this done properly.