Tow ball fitting

[bsafly]

Originally Posted by trikey

Scotch locks are the devils tool, put them in the bin!

Cannot abide Scotch locks, seen more problems than I care to remember caused by them.
(especially if they are in a damp area, for example a 75/ZT boot!)

[macafee2]

Originally Posted by alanaslan

Had a glance at the link you are using, Pin 12 is meant to be the earth ( line return ) for pins 9 to 13 not unused as quoted in the link. It should be a separate earth to that of pin 3 don't be tempted just link the pins use a different 2.5mm2 wire to a body earth point.
alan

most of the diagrams I have found on the internet say pin 12 is not used but one says it is trailer recognition. They also show pin 13 as the earth for 9.

macafee2

[macafee2]

Originally Posted by alanaslan

If you are worried about pin 9 being live all the time then put it on a ignition switched system either by a relay or by wiring it separate from the relay box please remember the thickness of the conductor on some of your aux wiring lines is meant to be much heavier than the conductors supplied in many 13 core cables ie pin 3, 9, 10, 11, 12, 13 all should have 2.5mm squared conductors whilst the rest are all 1.5mm Squared conductors.
Many suppliers supply caravan multi core cable that is only 0.5mm Squared.
Please make sure the wires are heavy enough wire is measured in cross sectional area of the conductor. I have seen the damage that overheating wires can do. Many cable meltdowns can be avoided with the fitting of a quality towing relay pack. remember to make sure you always have a good earth. ( line return ) as one earth wire: supplies many switched live feeds.
If you are worried about anything drop me a PM with your email address and I will do my best to give you the answers. In a word document.
Alan

when I can have proper access to my caravan I am going to check for a habitation relay and if it is working. I think the relay is part of the transformer/charging unit of the caravan.
I just dont leave the caravan connected to the car overnight any more

macafee2

[alanaslan]

Originally Posted by trikey

Scotch locks are the devils tool, put them in the bin!

Oh how true, I remember fitting a pair of seven pin electrics to a big Ford along with a set of parking sensors. It was in the Highland games field in Callander at a classic car club weekend meet.
The owner of the car was taking lots of photos and notes on what I was doing. He was very surprised by me writing down all the colours of the wires in the cars wiring loom and in the light clusters themselves. He was very surprised that the loom colours did not correspond to the cluster colours.
He was shocked when I cut the wires in the loom that I wanted access to then surprised when I tinned the ends of the bare ends of the cut wires and slid colour coded heat shrink up the cables. I then proceeded to run the switching relay cables into the three way joints in the loom then slide the heat shrink into place. He had never seen anyone solder wires he had only ever seen scotch locks being used. I explained that the method I used was permanent and guaranteed a good connection. I have to confess it has taken as long to type this as it does to do the job. When I had finished, I gave him a typed copy of the work I had done along with the fuse ratings for the new supply cables and a wiring diagram of the cars loom and the cars light clusters.
I had to extend the sounder cables on the audible sounder for his parking sensors so I could mount it at the front of the car under the dash board. He was a very happy man when I had finished. He could not understand why I had only charged him £13-50 for the parking sensors and £21 for the black and grey sockets and bypass relay. As his garage had fitted his last cars towing sockets and had charged over £150 for the job. Also they had used the dreaded blue crush blocks.
He had trouble understanding that fellow club members were more than welcome to a few hours of my time.
Everyone please take note scotch locks are a bad connection waiting to happen. Also there many club members who are happy to give their time to help other members at club meetings. Either that or they will talk you through a job.


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[COLVERT]

RE, those scotchlock type connectors.

I fitted a tow bar to my wife's Citroen C4 quite a while ago. If I had read about this type of connector before the installation I would never have used them.

However in the last 11 years they've been fitted, and towing a variety of trailers, they have never caused any kind of problem at all.

Are there other manufacturers of the ( scotchlock ) type of connectors ?? Maybe the ones causing trouble are cheap imitations.---( Chinese. )

I also used a Ryder TF2218/7H Smart logic relay unit.

[gozo ken]

After fitting the relays on my first 75, thinking I needed them,I wanted to buy another set,and to my surprise was told I didn't need them as it wasn't fully canbussed.
Sure enough I connected them to their respective lights etc' and they work.

[COLVERT]

Originally Posted by gozo ken

After fitting the relays on my first 75, thinking I needed them, I wanted to buy another set, and to my surprise was told I didn't need them as it wasn't fully canbussed.
Sure enough I connected them to their respective lights etc' and they work.

Actually I have a couple of friends who did the same as you did.--Surprisingly they had no problems either.----

[alanaslan]

I have probably fitted over 200 tow bars during my working life and a dozen since I retired in 2010. I will confess to having used dreaded scotch locks, which have worked fine and have fitted them with no connection or with intermittent connection.
I like to fit a bypass relay where possible. Mainly because it means only two wires are carrying current when the socket is in use. It also separates the vans electrics completely from that of the cars normal wiring. I have even been known to fuse both positive and negative supply’s to the seven pin sockets.
This came about because a members car had had a fire in its O/S rear loom and in the cubby. ( it was a tourer). What had happened was the owner had used a twin seven pin plug to thirteen pin adaptor cable, this had resulted in the cable on his caravan falling down and connecting with the ground. As he went on his Merry way the outer insulation started to rub away then the inner until the copper conductors became a mass of copper shorting out the circuits when he pressed the brakes or indicated. Like all good caravan drivers he drove with the side lights on whilst towing.
The result of his cable dragging along the ground had resulted in a dead short causing the insulation on the melt on the wires that were shorting out. The side light power had been jumped from one supply in the car to the two feeds the van uses. The earth/ neutral / line return, or what ever you can’t to call it was the worst affected as whoever installed the electrics has just used a 1.5mm cable scotch locked on to one of the wires going to a body earth point.
All the negative wires going to that body earth point and most of the other wires going from their connection in the car to the black socket were in a very sorry state.
Where possible I have always used a bypass relay whither recommended for that car or not. After this incident I have been fitting fuses to both polls supplying the bypass relay. I also always connect the negative conductor direct to a body earthing point never splicing into an existing earth wire. Yes it is overkill but for the sake of a pound it’s cheep insurance. I always add an addendum to the cars manual showing the bypass relay and the fussing of both polls on its supply I also give the colour of cables used and their size along with the fuse rating and type used.
I know it is total overkill but if fusing both poles stops a car fire, I am more than happy to break with conversion.
Safe motoring everyone
Alan


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