Tow bar electrics w140

[television]

Hi Stuart, it does not take much of a short to drain the battery, just 1amp over 2 days is 48 amps gone.

The 140 does not have any real problems in this respect, there is no wake up circuit on the car and all you have that can go down is things like seat controllers (memory)

I would get a cheap multi meter and connect it in series and see what the drain is, pulling out the fuses as you go

 

[shayes]

I have a multi meter but just can't get my head around how to use it. A fear of doing something wrong goes back to when I burnt out a solenoid as a teenager.

I'm charging the battery and going to see after full charge if with the fuse removed for the new parts it stays charged then its to do with the current flow. The guy says, if nothings switched on, then his wiring to an electrical point can't be the cause. But, i'm thinking, flow must take place via the alarm system? Reading up, on independent bulb systems, on hitches4less.com I read "QWhy do I need a power converter?
A: Electronics on many newer vehicles are not equipped to handle the extra amp load that trailer lights require. A power converter provides power directly from the battery, bypassing the electronics. This guarantees protection for sensitive electronics found on these vehicles. "

Now this says directly form the battery.

 

[television]

If this power converter is wired up all of the time, then it will drain the battery, its an inverter by name, and I can hardly see the point of it.

You cant get any thing free, an inverter is a circuit that converts the DC into AC as you cannot transform DC., the converted AC is then used to amplify the voltage, then convert it back to DC again, it s the same as a car jump starter, do you really need it

 

[shayes]

Is it a converter or just a connecting block previously run direct from the battery. I'm unsure.

Does it say "Ryder Smart 7 Bypass"

I have a 12v to 230volt converter at a caravan and this thing is ten times the size.

 

[shayes]

Is it a converter or just a connecting block previously run direct from the battery. I'm unsure.

Does it say "Ryder Smart 7 Bypass"

I have a 12v to 230volt converter at a caravan and this thing is ten times the size.

definately says to the battery -http://www.rydertowing.co.uk/towbar_relay_technical/towbar_relays_TF1016.aspx

but I will see if the battery discharges with the fuse out to be sure, and then change the cabling myself or get fitter back.

 

[shayes]

I would get a cheap multi meter and connect it in series and see what the drain is, pulling out the fuses as you go

I have the M.M and understand basic school parrallel and series battery connections.
Without responsibility or liability on your part, if you get the time I would be grateful if could pm me on what I need do. Set the mm at? Do I check current by removing a fuse and inserting probes instead, to get a reading when car switched off? Or is it more complex.

Perhaps I shouldn't go there.

I've just managed to fully charge the battery and am leaving the towbar fuse out. The thing about "converters" was a bit of a red herring or US talk presumeably for Lorry type trailer wiring and nothing to do with AC to DC or visa versa. DOH!!

Will see how battery looks tomorrow.

Stuart

ps Many thanks for the DVD thought. What a gentleman you are.

 

[television]

The multi meter should be set to the highest range on the amps DC, there is normally a special socket on the meter for this, you do really need a range of 10 amps, though 5 would be OK

On your car take off one battery lead, the minus neg lead is the safer one to work with, then 1 test lead from the meter to the battery and the other to the minus neg lead, the leads can be either way round, it does not matter, and that is it.

The current flowing will be displayed on the meter, with a battery in the car,turn the lights off, battery in the boot remove the bulb.

You can then just pull any fuse then look at the meter, keep doing this and you should come to it.

 

[shayes]

Just checked the Battery with MM set to 20 on DCV range, no boot lights in situ and reading was 12.49 so assume that battery has stayed healthy overnight which means Towbar electrics seemingly cause of problem (fuse removed).

Not done other tests as hesitant in having to disconnect battery. My locking system does play up, the boot sometimes not unlocking. Did check that window self closed when thumb held on remote control.

 

[shayes]

I cant think of what he has done, as the trailer was not even connected

Still monitoring situaton as battery seems to be at half charge even after sixty mile run the day before.
I do see what Fitter has done though every time someone lightly changes things slightly I wonder to what effect.
There is an extra battery terminal on the car (as photo) and instead of linking it with 2mm cable he has used two single 1mm. Now why the other side of the fuse is a four cable run off down tubing I'm not sure. However, the yellow is cut and the green although going to the fuse is cut off the other end when it reaches the Bypass. So, I guess (?)everything is as it should (although I only recall one red cable from battery on original wiring, perhaps it was bridged at the bypass. As everything seemed to work properly I'll restore the fuse and see what results. Battery low light does not come on in car so preying that altenator is OK. Have been having diffculty with boot.
Did read a thread on here about disconncting battery on an A140 and problems so, still not taken the plung on checking fuses. Sorry Malcolm he who dares (usually loses in my case)

Postscript
Now I look more closely is that terminal block truly independent of elecrical system? Seems to be a large black cable behind it. Rydertowing.co.uk says run off the battery.

 

[television]

Its very hard to work out what someone else has done when its not standard

 

[shayes]

I think I'll just re-route the twin wires and fuse direct to the battery below and should then be as specified.

Thanks for your input Malcolm.

 

[StevenMW140]

Hi Can someone email me the wiring instructions ?

I think i need a box or something to stop the bulb warnign light is that right ?

 

[StevenMW140]

Hi Im struggling to wire a towbar to my w140 500SE

Is there wirring instructions anywhere ? does this require a relay breaker ?

 

[television]

It would be easy to do it with a very low current relay, I will check later in the day to see if MB published a paper on this.

 

[shayes]

Need a Multiplex Bypass Relay - check google for 7 way universal bypass Relay for diagram.

Missing my Merc after huge expense of now being a Lexus owner. Also yet to fit the electrics to the Lexus Tow bar and unfortunately does not have the battery in the boot like the S Class so bigger job

 

[television]

Need a Multiplex Bypass Relay - check google for 7 way universal bypass Relay for diagram.

Missing my Merc after huge expense of now being a Lexus owner. Also yet to fit the electrics to the Lexus Tow bar and unfortunately does not have the battery in the boot like the S Class so bigger job

Miss you too Stuart

 

[EmilysDad]

.... Also yet to fit the electrics to the Lexus Tow bar and unfortunately does not have the battery in the boot like the S Class so bigger job

Isn't there a factory loom connection point for towing? My Vauxhalls have had for years

 

[shayes]

Isn't there a factory loom connection point for towing? My Vauxhalls have had for years

Not that I can find. Other owners say to run it from the battery up front to the boot.

BTW the Merc Tow bar electrics drain seemed to be sorted when I connected the Positive direct to the Battery via a fuse.