75ZT Community

Can I use 3a screw connectors on a towbar wiring loom inside the car boot?

I have fitted the towbar and sockets to the exterior and just need to connect the second hand wiring loom with relays inside the boot to the wires going to the rear light clusters (left & right). I ordered choc box connectors and they sent small 3 amp screw connectors for use in each choc box. Does anyone know if these small 3 amp connectors correct? Or too small?

There's a lot to the question, TBH. I'll start with the fact you mention sockets, so I assume you have two, 12N and 12S. The 12S carries the current for battery charging and fridge and 3A is not enough. On the 12N 3A is insufficient for the earth, and boderline for things like brakes, fogs if your trailer / van has two.

All of that said, chockblocks for wiring on a car are bad, almost as bad as bodgelocks (Scothlocks, spit) so I would only use them on my worst enemies car. Even though they are in the boot and shouldn't corrode, even the humidity can cause them to, but vibration is the big problem. A crimped splice, covered with adhesive heatshrink is a much better solution.

Thanks Duncan, I have the S/H double socket towbar with the s/h loom they used. But I only need to get a trailer board working to use a trailer as I expect to move house soon. Will it work if I only connect the trailer board wires? Being:-
Left & right indictors (2 wires)
Left & right tail light (2 wires)
Stop/brake light (one wire)
Earth (a big banjo wire connection and may be one other.

Do you have a bypass relay to fit as well? With one of those, yes the wiring you mention will be fine. But you will also need a power feed to the bypass relay. If you don't use a bypass relay, the extra power drawn by the trailer lamps will cause the light switch to think there is an overload. The bypass relay will also provide the trailer indicator warning function that you need. Did one come with the wiring harness? EDIT: I see you mention the relays in your first post. So yes it will work with the connections you mention, plus a power feed.

Thanks Duncan, Yes two relays are in the s/h loom I have. I just found this which seems to give a useful wiring layout. https://www.pfjones.co.uk/12n-7-pin-ele ... relay.html
I was wondering if for only a trailer board on a 7 pin socket, if I can wire just the lights and not the caravan and so leave out the 12v live feed to avoid risk. Or does not having that 12v live feed also switch off the relay?

Yes, the relay won't work without that 12v feed. But you don't need to fit the secondary socket no. Just a feed to the lighting relay.