Tow bar electrics w140

shayes

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Has anyone fitted a towbar to a W140 series? I don't have any exploded diagrams of the back of the W140 but assume a Witter will be much the same as I fitted to my W126 series which is a straight bar to four holes where the rear bumper fits + and underside part? Fact is, I haven't discovered the bracket holes so far which I thought would be obvious.

A further problem, will be the electrics, not so simple as the W126 where extra connections don't create warning signals.

I have read on another forum that I will need a black box and that this wiring harness connects to a seperate fuse perhaps direct to the battery, for Towing electrics. Or, is the connector and seperate circuit in situ and just requires the wiring into a connector socket in the car? If so, where is this placed.

Any help appreciated as I have bought a Trailer (yes - cart before the horse !!) and need to fit a Bar.

Thanks

Stuart
 

SilverSaloon

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Hi Stuart,

no idea on your model, but even my W124 estate didnt have holes for the towbar. The mount holes are there in the boot for the support brackets (no idea if yours will need those), but the actual holes needed for the long bolts that go from the bar under the car to the support brackets needed drilling myself and i dont think there was any guide marks either.
 
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shayes

shayes

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I had one fitted to a W123 Estate model and the fitting was each side, not at the rear bulkhead.

When I fitted the W126 I wrongly assumed that the bar which went underneath the centre of the car should have been bolted to the Spare wheel tray, but no hole. Didn't attach a piece of angle iron at right angles which came with the s/h bar. Oops. It took a trailer 600 miles and no calamity.

Anyway, with the W140 I have a further complication of needing to know if my Donut LPG tank prevents one being fitted. I have found a source for a bar, both Witter and Bosal and awaiting their comeing back to me on the question. Also, searching "another site" I found a helpful hotlink. A guy in Oz (Simon Claringbold) has a V12 and tows a Boat on a Trailer behind his! Not being a member I could not ask for helpful advice. He seems a most knowledgable guy and come sup in google V12 uberalles.
Also, the electrics seperate power supply is still worrying me.
http://www.detali.ru/cat/oem_mb2.as...722.370620&CT=F&cat=19B&SID=31&SGR=015&SGN=01
 

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I will take a look to see if anything is listed
 

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Hi Stuart, I have Emailed you the fitting of the bar instruction and the electrics
 
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shayes

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Thanks Jez.

Many thanks to Malcolm for the info which looks as though the idea is dead in the water as I have an LPG Donut fitted in the spare wheel well.

Quite a complicated set of requirements with oil cooler, integrated wiring loom etc., etc.

Anyone want a Trailer? I'm hoping the guy will relist it for me and save me the further expense of collecting. It's a sturdy beast and has ability to transport Motor bikes as well.
Near Basildon. PM me if interested.

http://cgi.ebay.co.uk/LARGE-TRAILER...3286.c0.m14&_trkparms=66:2|65:7|39:1|240:1318
 

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does the LPG prevent you from fitting the towbar from a legal perspective?
 

Uncle Benz

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JEZ's old bar is still in my scrap bin. It is a Witter, but the removable part with the ball is missing. It is a straight bar with two bolt fixing each end. It does not interfere with the spare wheel well at all...
 
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Uncle Benz removed the one fitted to mine a couple of weeks ago. PM him and see if he still has it.

Out of interest, did you have an electrics package fitted? i.e seperate fused circuit to the battery?

Still considering adding a bar as have found a s/h one but I can't put all the fixings in place, only the two bolts each side rear. Not even sure if I could fix the centre bolt as have LPG tank in s/w area. Quite sure it swill suffice as don't have an exceptional one off load to take over.

Really frustrating this as I want to take a trailer to France rather than buy a van or some other crap solutuon where I don't get to enjoy French roads with the Merc.
 
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shayes

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JEZ's old bar is still in my scrap bin. It is a Witter, but the removable part with the ball is missing. It is a straight bar with two bolt fixing each end. It does not interfere with the spare wheel well at all...

Just read your thread having not spotted it, and sent Jez a message.

I suspect even the Witter would be like the Bosal which should have side arms that bolt further back. Only needing the thing as a temporary addition for a six huindred mile journey. Is the removable ball section a twin bolted part or go to the back of the bar as in this diagram. I have a brand new Witter bar with ball unit but it is an angle iron bar, bought it for my late Safrane.

http://www.toys4cars.co.uk/instructions/017813.pdf
 
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shayes

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does the LPG prevent you from fitting the towbar from a legal perspective?


I'm glad you didn''t ask that question.

An LPG Tank is consideralby stronger than a petrol tank and so I don't think there is an issue and and please don't tell me if there is!!
 
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shayes

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update and regrettably answer needed.

I have had the towbar fitted and the LPG tank was not in the way of the bolt holes.

Gave the guy the electrics pack but he doesn't seem to have fitted it. Looked very neat job electrically and assumed everything hidden, but could not see the lead going to the + pos of the battery terminal. (There is what looks like a smaller red cable under the terminal block but this looks different to the one I had on the pack. Maybe integral radio cable?

Everything semed to work OK when he showed me, and no fault lights appearing on instrument cluster, but two days later after not using car, battery discharged. Had to charge to get car started. Ran yesterday for sixty miles, today showing half charge.

So, has the guy not put in the electrics pack and what is the consequence? I'll phone him this evening but I am wondering if there is a fuse I can pull and only use when need to have trailer board?
 

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

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

I spoke to him an hour ago and the only thing he tells me he did was to connect the power to an already existent power line with a fuse, seen to the far left of the photo, instead of a direct line to the battery as previous wiring (as taken from vendor car) shows with red lead and connector for battery terminal.
 

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shayes

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

Possibly a naive question but could a faulty lamp bulb cause a battery drain? Just drove off this evening and noticed "bulb out" warning light. What I think should be a 5watt rear inner bulb (but is a 10 watt??) was not working and the holder is a little charred, well brown. Checked other side and bulb and although black, (5 watt) working, and no sign of brown on the holder. Could I have found the problem, bulb holder or bulb got put in wrongly or twisted when putting back panel cover and has been arcing?

Will try a new bulb tomorrow, and see what state of battery power is.
My Father was an electronics engineer, why did I get custard and not his brain?
 
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The figures for those lamps are in watts, not amps,, this would not cause the problem as the lamp would have to be turned on, has the boot light switch become damaged so that the boot lamp is staying on, get your wife to climb into the boot and close it to check.


Electronic engineers:Oops::Oops: not a good line as you end up a total misfit in society the way that I have:(
 
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shayes

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The figures for those lamps are in watts, not amps,, this would not cause the problem as the lamp would have to be turned on, has the boot light switch become damaged so that the boot lamp is staying on, get your wife to climb into the boot and close it to check.


Electronic engineers:Oops::Oops: not a good line as you end up a total misfit in society the way that I have:(

Yup - I edited the link after thinking amps??? I hadn't put back the two festoons for the boot so they can't be the cause.

I had another look and can't see the relay box I gave the fitter but he said there is a seven way(?) relay. Is it a black box of octagonal shape that perhaps I didn't notice before just above the fuse he mentioned? Clutching at straws. if it still drains then I'll get him to put the power lead to the battery direct with a fuse and an isolator switch.
 

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I just cannot think what he has done when joining this up,,it is not good to just fit a switch, this could give you problems further down the line
 
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shayes

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I just cannot think what he has done when joining this up,,it is not good to just fit a switch, this could give you problems further down the line

Thanks Malcolm
Got up at 3am as started thinking something electrical could be getting hot if battery draining. Took out 20amp fuse. This morning battery charge low. Phoned fitter and he said he didn't think it was the tow bar electrics. He told me the converter(?) the part I supplied him with, was on the nearside wiring and sure enough it is in situ. He said he found the spare power line and fitted the 20 amp supply line. I said I'd check all lights were out when the trailer board was connected. Audible relay did make three beebs when I reinserted the fuse with the trailer board connected. Seems OK? no lights were on and the boot lights I had once again had removed.

So, could this be something else and coinicidence? Previous owner did say he had power drain if car left for a week. New battery installed. I tend to only use the car friday night and weekends and not noticed a problem before. Read a thread about the comfort relay and wondering? Also, there is a phone in the car and when I start the car and turn off the ignition can hear some wirring sound in the boot for ten seconds. Thought it was the aerial but the mast is broken or perhaps it has something to do with the Hirshmann chrome box next to the aerial is this for mobile reception(?).

Will monitor without fuse after battery recharged.

ps Still concerned that power to trailer lights does not come direct from battery terminal as kit I got, but fitter says shouldn't be a problem? Who am I to argue with soemone woh does the job for a living
 
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