Dedicated towing harness - Reverse issue

As I said, they are quick and cheap, if that's what you want then fine.

My phone master socket is not subject to the harmonic vibration of the sprung mass of a motor vehicle. My house would have fallen down if it was. Telecom applications use single solid conductor which gives a better outcome, still poor though.

I did not say manufacturers used scotch locks I was pointing out that they did not use Insulation Displacement connections, these are the principals that scotch locks use to make a connection. Many have tried, all have failed.

Cutting and soldering gives a 0 Ohm joint that can be made waterproof and corrosion resistant. Mechanical failure is 0% if done properly.

Scotchlocks give an unknown resistance to the connection, are open to moisture, promote corrosion, regularly fail mechanically and cause fretting of the conductor.

This not my opinion it is documented fact and there are many technical papers on the subject.

Disadvantages of solder method:

1/ It takes more time to terminate than other methods.

2 "Cold" solder joints can cause problems if the connector is not soldered properly to the cable, observing solder flow through the contact solder hole.

3/ Soldered joints between contact and center conductor can work harden if subjected to excessive vibration during use and develop micro-cracks followed by solder fatigue.

4/ Soldering can be inconsistent and subject to failure as a result of mechanical or temperature stresses.

5/ Care must be taken to control heat applied during the soldering process and not allow solder to wick or distort the cable dielectric

Time was when we would solder supply cables, that was around 45 years ago, now all are crimped.

That's all I'm saying on the subject, so we will have to agree to disagree.

I have to agree with xtrailman, if you don't want to use scotchloks then crimp, solder is not the most reliable method. If you want to do the job properly then heat-shrink over the crimp.

Personally I'm happy with scotchloks inside the car, never had a problem yet. Most official manufacturer car towing kits use scotchloks in my experience.

solder is not the most reliable method

Soldered joints are 100% reliable

Most official manufacturer car towing kits use scotchloks in my experience.

Not if you have a modern(ish) car, then it will be a dedicated plugin harness to be compatible with the CanBus system, and any advantages offered when the cars ECU knows it is in towing mode. Scotchlocks along with bypass relays won't give that.

Soldered joints are 100% reliable

Depends who is doing them. I have in the past come across 'dry' joints even in manufactured products

Scotchlocks give an unknown resistance to the connection, are open to moisture, promote corrosion, regularly fail mechanically and cause fretting of the conductor.

As with soldered joints the quality of connection is dependent on the operator and chosen sizes etc. IMO

Soldered joints are 100% reliable

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Depends who is doing them. I have in the past come across 'dry' joints even in manufactured products

Perhaps I should have added .......... me.

As in all things in this world, if it isn't done right it will fail, didn't think it needed additional explanation

My Vauxhalls had a factory connector for the towing connections & my last dedicated loom for my Omega used plug & socket that plugged onto the tail light and plugged the original plug/socket onto the new loom. I can't see any car manufacturer condoning the use of Scotchlocks when they spend so much in designing their cars.

When I was at work,  a big part of the fleet  (Some 800 vehicles) were Volvo chassis,  the only repairs we were allowed to make and claim for had to be done using OEM connectors. This came in the form of a Kit containing specific crimping tools for each type, Specific Pin release tools to get the connector out of the insulated sleeves and a selection of connectors(male & female) All contained in a camera equipment type case.  The kit cost in excess £3k . Nothing else could be used,

Any reputable garage or competent auto electrician will tell you scotch lock type connectors are a problem waiting to happen and will not use them. 

I would advise anyone to steer well clear of any towbar fitting service that uses them in the instalation.

Most official manufacturer car towing kits use scotchloks in my experience.

No absolutely not. I line with Milo's experience, all OEMs have a dedicated repair kit and dealers are contractually bound to use them. These do not and have never involved any type of insulation displacement terminal.

I totally agree that crimp and solder are the correct way to cut in cables but this assumes that you have the correct splice terminals and calibrated crimping tool. You probably don't and they are eye wateringly expensive. For the average DIYer the chance of overcrimping and fracturing the main cct when jointing the new wire if you have the wrong splice crimp is considered more prone to failure than a straight solder joint.

I totally agree twist and solder is not the ideal way to do it, but for the average 'solder once a year' type DIY, it is by far the best way.

With respect to the quality of a soldered joint, as I said in my initial post if you dont know what you are doing then find someone who does.

xtrail man, your technical reasons for not using solder are ripped from a website and are specifically referring to the application of open ended lugs onto power cables. They have nothing to do with the jointing of towing circuits. I know you really dont want to believe what I am saying but just google scotchlock failures and have a read.

I have had my C4 Picasso since new and when it was ordered I asked for a dedicated wiring harness to be fitted, I was persuaded to not go down that way! I took delivery and I quite often had problems with the fridge not working all of the time when towing and my reversing lights did not work on the 'van. But, I put off and put off and didn't do anything about it! Hindsight is a wonderful thing!

The car is now six and a half years old so decided that I would upgrade the plugs to a 13 pin. This was done yesterday and I was shocked to find that the wiring that had been used for the fridge was very thin (about 5 amp) and the relays were next to useless! The reversing lights had not even been connected up! I now have the correct kit with the correct wiring, so now when the reversing lights go on the rear car sensors are turned off. I will be going in to see the Service Manager at the Citroen Dealership along with the cable that was taken out, I know it is too late to get anything done about my wiring kit, but at least it might stop someone else from having dodgy wiring fitted.

And to think I have towed all over the UK, France, Holland and Germany with it like that. Scary!!!