tow bar wiring

[itchyfeet]

So I have a bike rack coming that will need a light board, I have a tow bar and I purchased a socket but that's as far as I have got.

So my questions are, will I need to upgrade the flasher unit or is it good for 6 lamps?
Do I need to do anything else to be legal other than wire it up as per this?

http://www.brick-yard.co.uk/VehicleSpec ... towbar.htm" onclick="window.open(this.href);return false;

I did search honest but found nothing

thanks in advance

[CJH]

I checked over the towbar wiring on mine last week - it's all scotchlock connectors attached to the rear offside cluster, with a couple of wires (left indicator, left tail light) taken over to the other side. Not the prettiest installation, but it all seems to work. I haven't checked the voltages with the engine running, but with the engine off there's some serious voltage drop - just over 10V remaining on some of the wires by the time it gets to the tailboard bulb sockets. If I didn't have other things higher up the priority list I'd be tempted to consider a headlight relay-type mod for the tailboard - maybe even for the rear lights themselves - but it would need quite a few relays.

But to answer your main question, the relay seems to cope ok with the flashers. Mind you, I haven't checked whether the PO upgraded the relay, but I seriously doubt it.

I think there's a requirement for some sort of repeater lamp/buzzer to show when the indicators are going on the tailboard - presumably so that you know if they're not working as expected. Others will be able to comment on whether this is a legal requirement.

[itchyfeet]

Thanks
I will be using the wago orange lever connectors in screwfix
I did read about the indicator tell tale here on p11

http://www.caravanclub.co.uk/media/1022 ... ing-mo.pdf" onclick="window.open(this.href);return false;

But it says regs came out in 1989 and my van is 88 so does it apply?

[bigherb]

Thanks
I will be using the wago orange lever connectors in screwfix
I did read about the indicator tell tale here on p11

http://www.caravanclub.co.uk/media/1022 ... ing-mo.pdf" onclick="window.open(this.href);return false;

But it says regs came out in 1989 and my van is 88 so does it apply?

Flashing indicators need a visual or audible bulb failure warning since they have been fitted. The vehicles indicators usually flash fast if a bulb fails, fitting a trailer board overrides that so an additional warning system is needed.

[itchyfeet]

Thanks bigherb

so lots of t25s out there with towbars what do people fit in the way of a warning system?

i have considered just taking the electrics off for the mot but would be nice to do it properly

it part of the mot as far as i know now so maybe vans will be failing if they dont have this fitted?

[AdrianC]

it part of the mot as far as i know now so maybe vans will be failing if they dont have this fitted?

Towbar electrics are only part of the MOT if you've got a 13-pin socket fitted, rather than the more usual 7-pin. TBH, I never bother with any kind of trailer indicator warning - buzzers tend to be inaudible and frankly I CBA to run a wire to the dash for a warning light. It's not an MOT issue at all (at the mo), and I don't find it much of a hassle, since I always check the lights on a trailer anyway. Honest... <uncrosses fingers>

[CJH]

Assuming you did run a wire to a warning light in the dash, how would the warning circuit work? I can't think how to wire it so that it would tell me that one or other of the trailer indicator bulbs or brake light bulbs was out, never mind how to make it reinstate the warning that one of the vehicle bulbs was out (as per BigHerb's point that the flashers go at a faster speed for non-trailer electrics).

[bigherb]

The simplest is just to fit a four pin trailer indicator relay with terminal C2 connected to the warning light/buzzer.
Or use the existing relay and fit a plug in midwife from someone like Ryder towing between the relay and fuse box.
All the warning circuits do is measure the amps draw for two bulbs and a side repeater, when the amps draw is exceeded then it flashes the warning to show the trailer bulbs are working.

[itchyfeet]

it part of the mot as far as i know now so maybe vans will be failing if they dont have this fitted?

Towbar electrics are only part of the MOT if you've got a 13-pin socket fitted, rather than the more usual 7-pin. TBH, I never bother with any kind of trailer indicator warning - buzzers tend to be inaudible and frankly I CBA to run a wire to the dash for a warning light. It's not an MOT issue at all (at the mo), and I don't find it much of a hassle, since I always check the lights on a trailer anyway. Honest... <uncrosses fingers>

Thanks for the replies,
this mot info is most interesting and confirms my suspicion that nobody bothers which is why i cant find anything on the search

so just going to wire it in

[AdrianC]

this mot info is most interesting and confirms my suspicion that nobody bothers which is why i cant find anything on the search

Sum total of what the tester's looking for on tow wiring...
http://www.motinfo.gov.uk/htdocs/m4s01000901.htm" onclick="window.open(this.href);return false;

[itchyfeet]

Thanks for the link