Towbar Fitting - Electrics

[8511swann]

The caravan thread just kicked me into sourcing a towbar and electrics for my saloon, and I had a question regarding electrics.

Is there a wiring kit that will plug directly into my loom/harness somewhere and will I require a bypass relay?. Or is it a case of having to cut and join wires into the loom.

And finally, is this price good:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290467140552

It's for my 2000 V6 Saloon.

Thanks,

Swanny

[ashb]

Looks a good price to me, i want to get a towbar for my ZT so interested in how easy it is to install.

Are there any kits where i won't need to remove (or cut) the bumper to fit it?

[8511swann]

I think the one above fits both without a bumper cut. Bumper removal is only about 8 screws.
http://www.discount-towing.co.uk/home/pdf/424E.pdf

[8511swann]

Apologies, I found this thread:
http://www.the75andztclub.co.uk/forum/showthread.php?t=23097&highlight=fitting+towbar

[HarryM1BYT]

The caravan thread just kicked me into sourcing a towbar and electrics for my saloon, and I had a question regarding electrics.

Is there a wiring kit that will plug directly into my loom/harness somewhere and will I require a bypass relay?. Or is it a case of having to cut and join wires into the loom.

And finally, is this price good:
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=290467140552

It's for my 2000 V6 Saloon.

Thanks,

Swanny

That one uses relays to bypass the can-bus lamp failure system - in othe words if a trailer lamp fails, you will not know about it. It is also a just the basic single outlet type, it will not supply the fridge nor charge the caravan's battery. The extra S socket will cost about £20 on top. Other than that, it is a good price.

Around £120 extra, will buy you the proper Rover 75 can-bus unit to use, instead of the simpler relay system. The actual fitting of the towbar, is the easiest one I have ever fitted on any of my cars. I would hope the one in the picture of the ad is not the one they actually supply, or that may prove to be unecessarily difficult ;)

[8511swann]

That one uses relays to bypass the can-bus lamp failure system - in othe words if a trailer lamp fails, you will not know about it. It is also a just the basic single outlet type, it will not supply the fridge nor charge the caravan's battery. The extra S socket will cost about £20 on top. Other than that, it is a good price.

Around £120 extra, will buy you the proper Rover 75 can-bus unit to use, instead of the simpler relay system. The actual fitting of the towbar, is the easiest one I have ever fitted on any of my cars. I would hope the one in the picture of the ad is not the one they actually supply, or that may prove to be unecessarily difficult ;)

Thanks Harry, much appreciated. I've never used twin electrics, as I tend to have the whole thing hooked up at home for a couple of days before hand, and never travel more than about 3 hours. The fridge (and my beer) is always nice and cold upon arrival!.

The bar does look very easy to fit. I might just fit it, and then get the local towbar guy to do the electrics. He's said he'll do it for £50 including the parts.

[8511swann]

Just bought these three items, for less than £100, so quite happy, but annoyed that I forgot to take the AL-KO ball off my old car!!:mad:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=230409320771

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=150529860794&ssPageName=STRK:MEWAX:IT

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=270694096417&ssPageName=STRK:MEWAX:IT

[fooman]

I posted the info below on another thread may be useful to you.

Some more notes - the 7 way relay includes a buzzer that sounds when the trailer lamp is working, so you know when it's not!

The second socket is for charging caravan battery & reverse lights.

Cutting the rear bumper is trivial, took me less than 60 seconds with a jig saw & you can't see the cuts once refitted. The whole fitment took me half a day mostly removing trim & wiring.

---

I’ve just finished wiring a tow bar on a tourer using a universal kit with a twin socket.

For single rear-lights-only setup you will need the socket & a 7 way relay that ‘repeats’ the light cluster signals without upsetting the can-bus system. The 7 ways can come with integral sounder / monitor for failed trailer lamps, which is a legal requirement now.

For twin setups you also need a split charge relay. These simplify installation as they only need one main 12v feed and detect engine running (though change of voltage) and switch the socket outputs, preventing a flat battery. You can share the 12v feed for with the 7 way relay. This feed should be suitably rated & fused.

I tapped the 12v feed from the fusebox tow bar socket using a big spade connector. The 7 way is connected by crimp connectors just behind the left hand light cluster (one wire run from the right hand indicator) you need to remove the fluffy side trim to access them.

This whole set up including tow bar cost me about £140 all new items. Hope this helps!

[8511swann]

Cheers Fooman, much appreciated.
Swanny

[Miff]

I posted the info below on another thread may be useful to you.

Some more notes - the 7 way relay includes a buzzer that sounds when the trailer lamp is working, so you know when it's not!

The second socket is for charging caravan battery & reverse lights.

Cutting the rear bumper is trivial, took me less than 60 seconds with a jig saw & you can't see the cuts once refitted. The whole fitment took me half a day mostly removing trim & wiring.

---

I’ve just finished wiring a tow bar on a tourer using a universal kit with a twin socket.

For single rear-lights-only setup you will need the socket & a 7 way relay that ‘repeats’ the light cluster signals without upsetting the can-bus system. The 7 ways can come with integral sounder / monitor for failed trailer lamps, which is a legal requirement now.

For twin setups you also need a split charge relay. These simplify installation as they only need one main 12v feed and detect engine running (though change of voltage) and switch the socket outputs, preventing a flat battery. You can share the 12v feed for with the 7 way relay. This feed should be suitably rated & fused.

I tapped the 12v feed from the fusebox tow bar socket using a big spade connector. The 7 way is connected by crimp connectors just behind the left hand light cluster (one wire run from the right hand indicator) you need to remove the fluffy side trim to access them.

This whole set up including tow bar cost me about £140 all new items. Hope this helps!

Where is the "12v feed from the fusebox tow bar socket"? Thanks.

[TEOC]

Where is the "12v feed from the fusebox tow bar socket"? Thanks.

Bump.

Just fitted the metal bits, suck on the 12V feed. :confused:

[HarryM1BYT]

Very much from my memory - look for a yellow with red tracer, might be loose behind the glove box / fuse box area.

[trikey]

These are the wires you are after, sometimes tucked down behind the plastic cover on the passengers LH side.

http://i297.photobucket.com/albums/mm215/v8_trike/SAM_1781.jpg

[Chuckles]

Am I missing something here?

When I had my 825 many years ago, there was a purpose dedicated socket on the cars wiring loom in the boot, ready to take the 7N electrics.

I have just bought my 2.0 Saloon and as yet not looked into the towing aspect, but was expecting the same facility, particularly with modern day electrics as they are now.

[Shabbs]

Very much from my memory - look for a yellow with red tracer, might be loose behind the glove box / fuse box area.

Is the yellow/red a switched live feed and what is the green?

[BX51 2.0 V6 Tourer]

Can I please have a little help from those with personal experience.
2001 Connie tourer - Hi line sat nav etc.
Ok so fitting a tow bar. That was the simple bit. Connecting up the electrics - fine I need the relay, did a bit of research and then sorting out the power feed to the relay. the picture from Trikey 13th Aug is what I am after.

Perhaps a better view is at #15 on this thread http://forums.mg-rover.org/showthread.php?t=366264

There are some more pictures. OK so dissembling quite a bit of the car now to expose the area around the fuse box
Here is what I can see

CLICK ON PICTURES TO ENLARGE

12258
As you see - no sign of the thick orange with the grey stripe ! Where is it !

12259
here is the view from the another angle - still nothing !

12260
nothing around the fuse box !

12261
still no sign !

12262
There was this loose fly-lead but this appears to have a purpose 2 socket connector on the end. (What is this for ?)

I have a car with highline nav and TV in it. Exactly where I want to come through into the area to the rear of the spare wheel under the deck floor there are two boxes with power to them, but I presume these are protected by a fairly modest 5 amp fuse. So I cannot use that.

Am I just being dumb and the wire and termination are still hidden out of sight or are some cars not equipped with the termination ? [As Chuckles remarks - this does somewhat beggar the question - why isn't there a fused power line to the boot area ? ]

If my car has no available termination - is there an unused fuse socket with terminal I can solder onto or do I need to buy a pack of them and stick one on the end of a wire and insert it into a spare socket on the fuse board ? If so - which one ?

[BX51 2.0 V6 Tourer]

OK so I needed to find a 12 v supply.
So I needed to get to the back of the in-car fuse box.

You can remove the screws that hold the the fuse box in place but it remains quite impossible to do anything with it, you need more access.
So that means taking the glove box out.

That means taking the 6 CD player (that fits very awkwardly, right in the centre of the box,) out. So that was 4 nuts underneath and then a flylead to be disconnected.

Glove box removal. Unscrew the 3 screws that fit along the top edge of the box into the dash. The lower fixings are hidden. Feeling across the felt that lines the lower part of the glove box, I felt 3 areas with hollows below them. I then lifted the felt (the glue is certainly selected for strength).

12292

This revealed 3 more screws, which could then be removed and then the glove box could be taken out.

This allowed far better access to the fuse box and I was able to rotate it.

12293

When I looked behind it I could see the orange and slate (OS) wire in a 3 block connector, taped to the harness.
12294
This shows and better view of the connector
12295
and again
12296
This is a feed protected by a 50Amp fuse from the engine bay fuse box. There it is noted as "Trailer".

I selected to put a 2 mm2 lead directly into the OS supply and ran that down the LH side of the car following the main harness. This was a little of an overkill in terms of supply but it means I have a good supply if ever I want to fit the 2nd socket to provide feed for another battery etc.

Passing the wire along like this does mean that you have a lot of side trim and carpet to lift and needless to say most of the clips break as you are removing them ! I was fitting it to a Tourer and so all the side trim had to come out in the load bay ! At this stage there was quite a pile of things that had come off the car !

Connecting up the relay was fine. I put a 25amp fuse at the relay, just as the power lead goes into it. I soldered into the normal lighting wires. With care, you can cut the insulation back and yet not cut any of the copper wires, then solder the signal feed for the relay onto the exposed copper then cover up with insulating tape. This means there are no breaks in the original harness and nothing extra to go wrong. I did intend to put the relay down between the two boxes at the rear of the spare wheel space, but that meant another set of soldered joints as the leads supplied with the relay were not long enough so I went for behind the LH trim up behind the wheel arch. You need a plentiful supply of cable ties to secure the harness back onto the various clips and secure in place.

I paired up the signal leads for the indicator lights to the LH side only, to save running another lead to the RHS harness. Annoying is the need to run a lead to the RHS harness to pick up the signal for the RH turn indicator. (More trim to remove !)

I will add a note to the instructions in the technical section. Nothing works when connected as shown because the White of the lead to the 7 pin socket needs to be Earthed. Again this was done by soldering to one of the main harness black leads that are on their way to an Earthing point.

Finding that supply too quite a bit of time, mainly as I dithered before deciding that I just had to remove the CD player and glove box. Stripping out all that trim was a big hassle for me as I had not taken it off a Rover 75 before and so I was not that familiar with the clip positions.

A lot of time and a lot of hassle but pleased with the outcome now. I do know that if I had taken it to a "professional" to be done, trim would have been broken, scotchlocks would have been used and so it would have worked for 1 year but not two and I would have had an endless argument about the trim that would only be solved by me purchasing more and replacing it myself.

Two recent events.

One
My wifes Punto went in for lock exchange after a thief had forced the locks and broken in. We must have been back and forth about 4 times to rectify trim broken by their fitters. After a final time when they broke the trim on the window surround, whilst changing the trim around the mirror, that they had broken when changing the door card, which they had broken when changing the lock on one door, I gave up and refused to let them have the car back. Get the trim - and I will fit it. And this was a Fiat main dealer ! Earlier the lock had come out of a door, on the end of the key (just like a lolly) when the salesman was showing this (very difficult) customer, what a good job they had done. I think my sarcasm - "oh that is interesting, are the locks meant to come out like that" was somewhat lost on the foreman.


Two
Neighbours - a lovely couple, husband unwell, had to leave work. Long sad story - no proper recovery, wife has to do most everything. Came to a conclusion so to put that behind them they bought a brand new car and had it fitted at the dealer with twin towing sockets so that they could tow their caravan to the south coast and take a very well deserved holiday. New car for holiday.

I came across them at a quiet junction in the road - not yet out of the village. Worried about the lights on the caravan. They had called the AA. I helped out whilst they were waiting - nothing working. Suggested it was most likely a fuse. Multimeter on the sockets - nothing. Traced the lead into the boot and up to the rear seat - no joins. They described dealer fitment. I went to the fuse box and with the handbook went through every likely fuse. All good. Found the feed for the supply - looked good. The AA man turned up - he would look after everything. I left.

3 hours later - AA man could not fix it car went back to the main dealer. It came back the next day. The main dealer had placed the fuse holder in the power supply not at any sensible termination point, but on the harness as it went along the sill in the rear footwell. Yes, not the best place for the fuse - should have written in the hand book on the fuse page where they had fitted the fuse for the towing harness. Best money paid, the customer could not have done any more - let down by poor fitting/attention to detail. Holiday started again around 30 hours after it should have. Were scotchlocks used - when will they fail ? Maybe they will be fine. My experiences is that I and too many of my friends have had then fail.

Was fitting it myself worth the hassle? Yes because it would be less hassle than the alternative. If you find a good and reliable mechanic treat him well. He will be worth his weight.

[spiny]

BX51 Just done the same as you, fitted towbar and original rover loom to a tourer, towbar was the easy bit, electric i did struggle with, the instruction book was worse than useless, but took tablet out to car and using photos found on here :bowdown: managed it.
Never have I seen such a pile of trim, :shrug: looked like I was breaking the car, ended up with head torches putting it all on, but really impressed that it all worked, and impressed with the way the 'proper' loom works on lights, sensors etc.
very gratifying when it was done though!

[HarryM1BYT]

Was fitting it myself worth the hassle? Yes because it would be less hassle than the alternative. If you find a good and reliable mechanic treat him well. He will be worth his weight.

An interesting read and unfortunately - all very true:}

I will just make the point that I personally would always run at least a 4mm from the front to the back as the main feed, to avoid volts drop. You then have spare capacity for caravan battery charging, the fridge and the lights without too much impact upon the voltage when it eventually gets to the back of the caravan.

My OS didn't terminate in a plug, it was just bent over and taped. Your thin green to the light switch, seems to be already at that plug, but mine had to be run across to the switch.

[BX51 2.0 V6 Tourer]

Just doing my ebay feedback - I recommend :

Towbar £78
http://www.ebay.co.uk/itm/380393787800?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Relay £14.20
http://www.ebay.co.uk/itm/230695503231?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

Free delivery
Total 92.40


Very good quality and price.
And for putting back on our little mountain of trim - clip for B post etc part number EYC106710 (yellow) - available in white at bresco
£7.49 for 15. part number AP3954P
http://www.bresco.com/acatalog/BMW.html

[matada34]

So is this orange feed defo 50 AMPS?

I can use this to power both 12 S and N electrics?

Thanks Matt

[HarryM1BYT]

So is this orange feed defo 50 AMPS?

I can use this to power both 12 S and N electrics?

Thanks Matt

If you look in the under bonnet fuse panel, there is a spare place for a fuse link, which is the fuse link for the towing electrics, which is marked as 50amp. The fuse link is the type with metal arms, designed to be installed with two screws, with the fuse part black plastic.

From there (it may need connecting at the fuse box), it ends in the orange/slate which is lose behind the glove box.

50amps seems to be excessive, 30amps should be enough, but additional fuses will be needed at the rear, where you split the main feed down.

[matada34]

Ok :) thanks.... Why doesn't the user manual show this fuse along with all the others?

[HarryM1BYT]

Ok :) thanks.... Why doesn't the user manual show this fuse along with all the others?

The symbol on the lid of the fusebox for that fuse way, suggests reading the handbook.

[matada34]

Today I did most of the electrics on the 75 tow bar.

I found this feed which seems to be permanently live, the confusing but is that I have a spare space for a 50amp fuse (metal one screwed down), on the fuse box lid it shows this as a car symbol with arrows pointing to the rear.

I assumed this was the trailer 50amp supply but I'm a little confused as to why there is no fuse yet it's live?!

Any thoughts would be great

Cheers

[HarryM1BYT]

Today I did most of the electrics on the 75 tow bar.

I found this feed which seems to be permanently live, the confusing but is that I have a spare space for a 50amp fuse (metal one screwed down), on the fuse box lid it shows this as a car symbol with arrows pointing to the rear.

I assumed this was the trailer 50amp supply but I'm a little confused as to why there is no fuse yet it's live?!

Any thoughts would be great

Cheers

One end of the fuse way is and will be permanently live, it is fed from the bus bar, which in turn is fed straight from the battery. The other end of the fuse only becomes live when the fuse is added.

So basically your live feed from front to rear of the car, is live all of the time and usually is fed into a voltage sensing relay in the boot, which in turn switches the two supplies to the van battery and fridge. Neither than should be powered, except when you start the engine and the relay senses the voltage rise and then closes.

If the orange /slate is live, with no trailer supply fuse installed, it suggests that someon has connected it to the wrong fuse, which is remarkably easy to do.

[matada34]

When you say somebody... Do you mean the factory?

The connector was still taped nicely to the loom from the factory.

I just read on the forum that this wire is a permanent 20A feed?! Just trying to find the post...

[matada34]

Previous post...

Quote:
Originally Posted by humphshumphs
I am looking at running a 8awg cable with a 50amp fuse inline (as I have the cable/fuse) that is going to be perm.live.

I'll run the cable and connect it all up
There is a 20amp live all the time feed just behind the glovebox, which is normally only used for a trailer supply, why not make use of that?
__________________
Harry

[HarryM1BYT]

When you say somebody... Do you mean the factory?

The connector was still taped nicely to the loom from the factory.

I just read on the forum that this wire is a permanent 20A feed?! Just trying to find the post...

Confusion!

The cable only becomes live, a permanent live one, when it is plugged into the under bonnet fuse panel. If you un-bolt the fuse panel and raise it, you should be able to find the other end of the wire underneath.

Remember you need to not only fit a cable front to rear to allow for the current, but also big enough to cope with the volts drop. Usually this means at least 4mm, better is 2x 4mm or a 6mm.

[bugsley999]

My 20 year old 4X4 engine blew on the M62 a few weeks back :mad:

However, replaced it with 75CDTi Tourer auto :D with just 72k miles in not bad nick. Couple of niggling little faults that I'll may be back here for advice on a bit later.

But for now, to the point of this post. Witter towbar physically fitted (**** blow-up drawing wasted me some time figuring why bits were not missing!) and now on to the electrics with a couple of very basic questions.

I note from this thread that it seems folks come down the nearside (left) of the tourer and take out all the trim and it's a bit of a pain. (are there any drawings available showing where the fixings are on the forum?) Why not come down the right side where the CD changer is and terminate everything there where there is easier access and I suspect all the trim will not need to be removed?

Standard 20mm "electrical" glands would seem ideal for cable entry purposes rather than just grommets. Where is the best place to come through the rear metalwork with the cables?

Any other advice BEFORE I start?

Thanks.

Regards

Bugsley (Knottingley)

[RPWC]

I just drilled a hole at the top of the spare wheel well,that way you don't get water ingress and it's handy for the wiring harness.

[COLVERT]

I ran the power supply directly off the battery, through an inline fuse and then underneath the car to the rear. In through the wheel well.
No work inside the car; no trim removal. Took all of half an hour.--:eek::eek::eek:

[IverRover]

Posted this question earlier on the technical help section and maybe someone here can help please.

Already fitted a towbar and 12N electrics but we have now gone and bought a caravan so I need to wire up 12S socket.

51456

51457

Connected the wires between split charge relay shown in photo and towbar socket, and now need to connect power feeds.

Please correct me if I'm wrong (probably), but looking at running a wire with a 20amp in line fuse for the constant 12v feed, from a thick brown and black tracer wire on rear of passenger fusebox.

As per the instructions in the other photo at point 4, wire to Ign terminal on relay, I am stuck where to take the feed from. ' 12v when ignition on but NOT when starter motor is being operated, such as supply to wipers'.

Pointers please :shrug:

[HarryM1BYT]

As per the instructions in the other photo at point 4, wire to Ign terminal on relay, I am stuck where to take the feed from. ' 12v when ignition on but NOT when starter motor is being operated, such as supply to wipers'.

Pointers please :shrug:

Most installers these days use a voltage sensing relay, mounted in the boot area, rather than the warning light switched type that you have. The reason being that the later type involve more work to install and can be tricky on a modern car to actually use.

The feed you mention behind your glove box, is probably not even connected to the engine fuse box, it will be tucked up out of the way under the fuse box and will need a crimped terminal fitted and plugging in to the underside.

Can I suggest that for best results you do things this way?

Connect the above feed to the fuse box via a 30amp fuse, in the box - the correct fuse way for a trailer supply is marked.

Run at the minimum a 4mm or better a 6mm main feed from behind the glove box into the rear of the boot, close to your tow bar. That will then be an unswitched permanently live feed.

Add a voltage controlled relay on the end of it, with two outputs, one to the fridge circuit, the other to the caravan battery charging circuit. Insert a fuse of 20amps into each of those two circuits, so if there is a fault on one circuit it doesn't blow both circuits.

The larger than normal feed, makes for both your fridge and battery to receive higher voltage, less volts drop along the relatively long cable run. Both will work much more efficiently, with less voltage drop.

The voltage sensing relays sense the voltage rise, when the engine is started and fall when the engine is stopped. It may need some fine adjustment via a tiny screw, to operate correctly once fitted.

[IverRover]

Most installers these days use a voltage sensing relay, mounted in the boot area, rather than the warning light switched type that you have. The reason being that the later type involve more work to install and can be tricky on a modern car to actually use.

The feed you mention behind your glove box, is probably not even connected to the engine fuse box, it will be tucked up out of the way under the fuse box and will need a crimped terminal fitted and plugging in to the underside.

Can I suggest that for best results you do things this way?

Connect the above feed to the fuse box via a 30amp fuse, in the box - the correct fuse way for a trailer supply is marked.

Run at the minimum a 4mm or better a 6mm main feed from behind the glove box into the rear of the boot, close to your tow bar. That will then be an unswitched permanently live feed.

Add a voltage controlled relay on the end of it, with two outputs, one to the fridge circuit, the other to the caravan battery charging circuit. Insert a fuse of 20amps into each of those two circuits, so if there is a fault on one circuit it doesn't blow both circuits.

The larger than normal feed, makes for both your fridge and battery to receive higher voltage, less volts drop along the relatively long cable run. Both will work much more efficiently, with less voltage drop.

The voltage sensing relays sense the voltage rise, when the engine is started and fall when the engine is stopped. It may need some fine adjustment via a tiny screw, to operate correctly once fitted.


Thanks for that. Off to get the relay and wire you suggest now.

[HarryM1BYT]

Thanks for that. Off to get the relay and wire you suggest now.

I have been asked for more details on the voltage sensing relay. The one I suggested is called the Smartcom. It should be a stock item in most good car accessory shops, certainly in caravan parts suppliers stock.

It has a small adjustment on the unit to set the trigger voltage. It may need some adjustment once fitted, so that it only makes when the engine is running and the voltage rises. This type of relay is very sensitive to voltage drop between the fuse box and the relay at the back. There have been cases where a less experienced fitter, who doesn't appreciate that cables need to be sized for both current and voltage drop, have installed cable sized for the current alone.

You then get a situation where the voltage rises, the relay closes, which then puts the cable under load. The voltage then drops and the relay does what it should and opens again - rinse and repeat, until you arrive at your destination, with an under charged battery and a fridge which has defrosted.