Towbar wiring diagram?

[Jon Tilson]

Have any of you ever put a towbar on your dolly? I have one mecahnically fitted but the man who did wasnt up to doing the electrics...<br>
I can do it myself but only if I know what goes where, so if anyone could point me in the direction of a suitable wiring diagram I'd be full of grate...<br>
I presume these sockets are all standard aren't they?<br>
Just a pinout list would probably do...<br>
<br>
Jonners

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[dollysteve]

<!--EZCODE LINK START--><a href="http://www.rydertowing.co.uk/trailer_to ... <!--EZCODE LINK END--><br>
Should be all you need.

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[tinweevil]

I hate scotchloks. Evil, nasty loomwreckers.<br>
<br>
As a temporary fit crimp red piggyback blade connectors like these:<br>
<!--EZCODE IMAGE START--><img src="http://www.vehicle-wiring-products.co.u ... es/rpg.GIF" style="border:0;"/><!--EZCODE IMAGE END--><br>
onto the 7 wires. They are a different width to the ones on the rear lights but the socket holds well enough and the piggyback blade can be slipped behind the rubber jacket of the connectors on your loom. Zero buggering of your loom.<br>
<br>
I need to order some narrow plugs and sockets to make up proper piggybacks for Blue? Are you going to TDCIR Jon?<br>
<br>
Julian

<p>1978 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/704">Dolomite Sprint</a><!--EZCODE LINK END--> Blue, a bit tetley. - Current daily drive.<br>
1972 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/754">Spitfire IV</a><!--EZCODE LINK END--> No name, in bits.<br>
1968 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/705">GT6 II</a><!--EZCODE LINK END--> Little blue, nice!<br>
1973 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/755">Dolomite Sprint</a><!--EZCODE LINK END--> VA41, seriously tetley.<br>
1980 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/864">Dolomite 1500HL</a><!--EZCODE LINK END--> Orange, really quite tidy.</p><i></i>

[Jon Tilson]

I'd love to but I think I'm busy...<br>
Thanks for the info though guys.<br>
Tin I'm near enouh to drop over and pick up some bits and have a beer...<br>
<br>
You too Steve. Maybe we should have a 3-some..<br>
<br>
Jonners

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[1300dolly]

there are two types of socket. 12n for trailers and 12s for caravans. as said do not use scocth blocks there are a fire waiting to happen. make sure you wrap up the connections well with electical tape.<br>
<br>
J.

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[dollysteve]

I need to catch up with you to give you the paint so it would be an idea to combine it with a beer or two.<br>
The link I put in was for 12n as I couldn`t see a Dolly pulling a caravan, the S stands for secondary I believe, meaning it will run your fridge etc.

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[Jod Clark]

Firstly, you will need an uprated flasher unit.<br>
<br>
Secondly, you will need the buzzer relay that sounds when the trailer indicators are working. I know we had one left over when I finished Alun's towbar on his 166 but I'm not sure whether I've got it or Al has.<br>
<br>
Thirdly, there's nothing wrong with Scotchloks when used correctly, its only numpty nob-heads that take a supply for their billion watt spotlamps or magawatt amplifiers from the interior light circuit that start fires. Scotchloks are used throughout the towbar industry and have been for many years.<br>
<br>
Fourthly, I would consider adding a relay to your brake light circuit, the only Dollies I've seen with knackered brake light switches have been cars with towbars on..... Seeing as you'll be switching twice the wattage through the same switch it would make sense.<br>
<br>
Happy sparkin'<br>
<br>
Jod

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[tinweevil]

Either one or two Jod, the buzzer is required if you have a secondary relay driving the trailer indicators. This is because if a bulb fails you would not see a speed change in the dash warning lamp. If you have a flasher relay that can cope on its own you will see the speed change. The flash speed with a trailer connected on a standard relay is different to the speed without but thats fine, there's no specific speed requirement.<br>
<br>
Third, slice through approximately 80% of the insulation on a wire, insulation which also serves as the strain relief and anti kink and anti corrosion? No thanks. They may well be used but how many fitting warranties last long enough for this sort of thing to be a consideration? That'll be the round number.<br>
<br>
Fourth, the brake lights are fused at 17 amps along with everything else. All parts of the circuit should therefore be capable of carrying in excess of this in the fault condition otherwise the fuse is not the weakest link in the circuit. The fuse is there to protect the switch etc not vice versa!<br>
<br>
No sparks in my wiring thank you.<br>
<br>
Tin'<br>


<p>1978 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/704">Dolomite Sprint</a><!--EZCODE LINK END--> Blue, a bit tetley. - Current daily drive.<br>
1972 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/754">Spitfire IV</a><!--EZCODE LINK END--> No name, in bits.<br>
1968 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/705">GT6 II</a><!--EZCODE LINK END--> Little blue, nice!<br>
1973 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/755">Dolomite Sprint</a><!--EZCODE LINK END--> VA41, seriously tetley.<br>
1980 <!--EZCODE LINK START--><a href="http://www.triumphowners.com/864">Dolomite 1500HL</a><!--EZCODE LINK END--> Orange, really quite tidy.</p><i></i>

[Jod Clark]

Guess my three years in the towbar game was wasted then, huh?<br>
<br>
Without a better flasher unit the indicators will still flash at a steady rate but will 'strobe', i.e be illuminated for 5% of the cycle and out for the remaining 95%. The 8FL unit is not up to the job due to the bi-metallic strip design. It takes a fraction of a second to heat up and break the circuit, then ages to cool down enough to remake the circuit and start the whole cycle again. You DO need either a visual warning on the dashboard or an audile warning inside the car that the <!--EZCODE UNDERLINE START--><span style="text-decoration:underline">trailer</span><!--EZCODE UNDERLINE END--> indicators are working, its the law.<br>
<br>
I saw literally hundreds of towbars fitted in the short months I was at Towequipe in Nuneaton and not once did they have an installation come back due to faulty wiring. Scotchloks, whilst not ideal, are simple and quick and do not necessitate actually cutting a wire in half. They are also fully insulated. Strain relief? Are you sure? no part of the loom should be under strain or you'll derate even an unmodified cable. I would prefer to use the piggy back connectors (in the correct size) as mentioned above as long as they're fitted with a proper crimp tool, not one of those things that also cuts bolts and strips wires. They're as much the right tool as using normal pliers.<br>
<br>
The brake light switch is designed to switch 42 watts in total reliability, almost 4 amps. With a trailer connected the load doubles and the switch may get pissed off. It happened to my car and various Ford vans I've used. The fuse doesn't really have much to do with it and neither does fault condition, as hitching-on a trailer seldom constiutes a fault. Hitching on a caravan however, now thats ALWAYS a fault.<br>
<br>
'Happy sparkin'' is not a reference to arcing in the wiring, more to wish you enjoyable fiddling with electrical stuff.<br>
<br>
Jod<br>
<br>


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[Jon Tilson]

are these those blue foldover thingiies with a razor blade and two slots in it on the inside? Horrible devices.<br>
I thought I'd try and find some bullet joiners in the existing loom. Failing that the connectors Tin mentioned are ace. I alrady have loads...<br>
I here what you say about the flasher unit...<br>
Thought I'd take out the rear indicator bulbs if the trailer was plugged in <!--EZCODE EMOTICON START :rollin --><img src=http://www.ezboard.com/images/emoticons/roll.gif ALT=":rollin"><!--EZCODE EMOTICON END--> .<br>
Not sure I can be arsed with a relay for that extremely rare trip to the dump with my mates borrowed trailer and the landy ill...<br>
I'm thinking it just looks naff with the wire wrapped round the tow ball...<br>
Useful info and ideas though guys and TVM to you all.<br>
Jonners

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[redrichie]

are indeed the blue plastic foldover jobbies. As Jod says, they're perfectly fine to use on such low current and relatively "unimportant" wiring like a tow bar electrics.<br>
<br>
I wouldn't use them, but thats because of my training in Aircraft Electrics, and the access I have to professional aircraft standard wiring tooling.

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