Towbar Wiring - S211 - Help please!

[5tephen]

I have fitted a towbar to my 2005 e320 estate. I was sold a 7 pin wiring kit with a relay. I've found the indicator wires but the side/brake seems to be the same wire. Side/brake bulb is a single filament bulb. Do I need the more expensive plug in wiring kit dedicated to the car? If so can anyone recommend one.
Thanks
Stephen

 

[pmcgsmurf]

Can't help sorry, only ever fitted a dedicated one that goes into rear SAM.

 

[5tephen]

That's the route I think I'm going to have to take, but as I have the relay one I was wondering if it can be used.

 

[Merc220cls]

I agree, dedicated electrics are the best route nowadays.
I used to fit tow bar & electrics back in the day when car electrics were simple but with modern CanBus systems etc. dedicated ones are best.
My 2017 CLS Shooting Brake tow bar wiring was the easiest I’ve ever fitted, simply plug & play so to speak.

 

[pmcgsmurf]

Agree, I did this on the W211 and all just plug in.

 

[toolman1954]

Hi,
your wiring should not not be too different to mine, pull off the near side rear panel for the wiring, from the photo you can see where I have exposed the wires. car wiring... Green to red to connection 6 of TEB7AS
Black / green to green to connection 3
Black / white to yellow to connection 1
Red / black to black to connection 7 ..... these are the only "lights" wires, the rest of the connections from TEB7AS go elsewhere. You should have a wiring diagram with your wiring kit, most use a similar TEB7AS so you can work out what is what, or else get yourself a pointed circuit tester and prod it into the wires and test what is what when it lights up. This all works ok for me. The only problem I found was that the tow hitch causes the parking sensors to bleep. So just turn them off. If you use a proper wiring kit, then also factor in the cost of getting the car onto a STAR to tell it to ignore parking sensors. Chaep kit works fine for me and I just remove tow hitch when I am not using it.

Steve

 

[320Alan]

I fitted my own tow bar but chickened out say the wiring and got an auto electrician to wire it up and glad I did. As the s211 has led rear lights so it was a right ball ache and needed a specific wiring really to fit a 7 pin socket.

He started with a standard realy, oh you have leds ok back in an hour, oh this into work either looks like I need to order one in. The £50 job was £120 and I'm sure he didn't make much out of me after the time he spent.

Ps parking aensens were knackered before haand so no idea if they work with the tow bar.

 

[toolman1954]

Apologies for some slight **** up on my description,............... just ignore the "to connection " 3../...1../...7 .. ..as I wrote... .. these are the output terminals for wires to the 7 pin plug and need wiring as per the instructions to European Standard.

So Vehicle side of relay ... as per the new TEB7AS diagram below .....
Green to red............Brake lights
GN/BL to green..........R/H indicator
BL/Wh to yellow .........L/H indicator
R / Bl to black ..........L/H tail light
White to Earth
Brown .........R/H tail light unused.
On my wee old Freedom Microlite caravan, I had no reversing lights, nor fog lights so these wires were not used. You can see what is what in the photo.

@320 Alan..... I presume your auto elec started out not using a TEB7AS ( £20 ish off Ebay) which just uses a low voltage to trigger the relays inside of the TEB7AS to accommodate LED lights. £120??? mmmmm.

Steve.

 

[Ted]

Problem comes when they use pwm to drive a single filament bulb for tail and brake lights.

 

[5tephen]

Can't help sorry, only ever fitted a dedicated one that goes into rear SAM.

Nice looking imp. pmcgsmurf,

 

[5tephen]

Problem comes when they use pwm to drive a single filament bulb for tail and brake lights.

Thats my problem

I don’t think the TEB7AS, which I have, will work as I can’t find a separate wire for the Brake/ side lights, toolman1954, my E320 is a 2005.

 

[Ted]

Thats my problem

I don’t think the TEB7AS, which I have, will work as I can’t find a separate wire for the Brake/ side lights, toolman1954, my E320 is a 2005.

There won’t be a separate wire.
You could run a wire from the front sidelight or number plate light, and another from the third brake light maybe?

 

[5tephen]

There won’t be a separate wire.
You could run a wire from the front sidelight or number plate light, and another from the third brake light maybe?

I was wondering that too. Next find the feeds to the tailgate.

 

[Lakey800]

Did anyone get to the bottom of this please I have a s211 with led light at the rear I have used two different bypass relay kits with no success it the brake / side lights that are the problem?

 

[IonutIonut]

Apologies for some slight **** up on my description,............... just ignore the "to connection " 3../...1../...7 .. ..as I wrote... .. these are the output terminals for wires to the 7 pin plug and need wiring as per the instructions to European Standard.

So Vehicle side of relay ... as per the new TEB7AS diagram below .....
Green to red............Brake lights
GN/BL to green..........R/H indicator
BL/Wh to yellow .........L/H indicator
R / Bl to black ..........L/H tail light
White to Earth
Brown .........R/H tail light unused.
On my wee old Freedom Microlite caravan, I had no reversing lights, nor fog lights so these wires were not used. You can see what is what in the photo.

@320 Alan..... I presume your auto elec started out not using a TEB7AS ( £20 ish off Ebay) which just uses a low voltage to trigger the relays inside of the TEB7AS to accommodate LED lights. £120??? mmmmm.

Steve.

Hello, is there any chance I have your contact number in case I get stuck with the wiring?
Tomorrow I'm installing on a W212 and I have some confusion
Thanks
John

 

[MJJ]

Did anyone get to the bottom of this please I have a s211 with led light at the rear I have used two different bypass relay kits with no success it the brake / side lights that are the problem?

Could you take the tail light feed from the number plate illumination, and the brake light feed from the high level brake light?

Another option is to buy an aftermarket wiring kit that plugs into the relevant SAM modules. When I was researching this many years ago, the kit manufacturer of choice seemed to be a german brand called Jaeger, and I recall a german retail site being the place to buy from. Plug and play wiring kits were generally around £130 at the time.

Martin.

 

[m80]

I'm 'assuming' the 211 rear lamp is a 21 watt and fed with reduced voltage for the tail light.
Is there a reason the trailer 21 watt lamps couldn't be fed same style from the 1 wire of the 211?

 

[tjamesbo]

bump mate having difficulties with towbar elecs on his 211