Bypass relay

[HDAV]

Trying to help a friend out I have only used plug and play looms in my cars but the cost is quite high it’s only a basic unbraked trailer so 7 pin only.

Anyone recommend a relay? Assume it just splices into the rear light and pick up on other rear light for both indicators and a 12v feed for the relay?

It’s a Ford if anyone recommends one

[Salty Pete]

I have no idea what you are talking about!

[paintman]

Old way before modern electrics for the 7N socket was to splice the socket's wires into the relevant wires at the rear light clusters.
No separate relay but might have had to replace the car's existing indicator relay with a heavy duty one.
My 1986 RRC was done like that by a previous owner using scotchloks (!) even though it has a 'plug & play' socket in the wiring.

Relay was used on the 7S to give power to the caravan internals.

Modern cars electrics can be easily upset so plug & play may safer.

[HDAV]

Originally Posted by paintman

Old way before modern electrics for the 7N socket was to splice the socket's wires into the relevant wires at the rear light clusters.
No separate relay but might have had to replace the car's existing indicator relay with a heavy duty one.
My 1986 RRC was done like that by a previous owner using scotchloks (!) even though it has a 'plug & play' socket in the wiring.

Relay was used on the 7S to give power to the caravan internals.

Modern cars electrics can be easily upset so plug & play may safer.

Plug and play is £230....plus coding to the car ecu .bypass relay is £8-£30

The bypass relay uses a splice into light cluster to trigger the trailer lights but they are independently powered so don’t upset the “modern electronics” by overloading the circuits they are common off he shelf units

[HDAV]

Originally Posted by Salty Pete

I have no idea what you are talking about!

One of these for a Ford https://www.towsure.com/smart-7-way-...xoC_s8QAvD_BwE

[paintman]

Various sites with instructions for fitting the one in your link but no idea whether it's suitable for your friend's car.

May be better asking the question of the supplier or on a make/model specific website.

[HDAV]

And there was me thinking I might get some useful responses from people who had experience with the subject ��

[Salty Pete]

Originally Posted by HDAV

And there was me thinking I might get some useful responses from people who had experience with the subject ��

Obviously not many people use them.

Trailer lights are LED these days and draw stuff all power and installing one of those is only another thing that can go wrong.

[HDAV]

Most here are still bulbs not LED, have heard some led can upset vehicle electronics

[69cmw]

This usually fixes any issues if your car doesn’t like LED trailer lights

[paintman]

Originally Posted by HDAV

Most here are still bulbs not LED, have heard some led can upset vehicle electronics

Common topic on later Land Rover sites!

[Pikey Dave]

Originally Posted by 69cmw

Attachment 136087

This usually fixes any issues if your car doesn’t like LED trailer lights

If you’re handy with a soldering iron, a couple of 21W resistors does the job too, costs around a fiver.

[HDAV]

Originally Posted by 69cmw

Attachment 136087

This usually fixes any issues if your car doesn’t like LED trailer lights

£62 ??? Trying to save money here ......

[Fender]

Originally Posted by HDAV

And there was me thinking I might get some useful responses from people who had experience with the subject ��

Originally Posted by HDAV

£62 ??? Trying to save money here ......

The tone of your posts are coming across as mildly condescending, you could always try and be a little politer, you might find your thread gets more attention, IMHO

[69cmw]

Originally Posted by HDAV

£62 ??? Trying to save money here ......

Trying to save money and boats isn’t the best combination 🤣

[Last Tango]

I've used one before a few years ago, worked fine. The issue has more to do with the tailight setup the car has than the trailer lights. There's always "fix-arounds" that'll resolve any issues on the trailer lights. I'd say the car will fall into three categories. Simple bulb tail lights...no problem. Tail lights with CAN bus monitoring. (Dash "Bulb out" warnings)...should still be ok if the relay specifies "CAN Bus" compatible. The other is vehicle with rear LED lights and now your creeping into dubious territory. I'd take the hit for the factory unit rather than risk blowing something on the car. I was at a local van hire company who rents out VW Amaroks and their trailer hookup electrics will only work with LED trailer lights. (Much to the fury of the customer who had just brought one back while I was in their waiting room) so it might not be that straight forward.

All just my opinion.

[HDAV]

Thanks last tango, they are normal can bus lights so any canbus relay could be used. Was hoping for a recommendation for one as there isn’t much obvious difference between the £8 eBay special and £30 units it’s not my car but I might end up doing the wiring or advising by video

[Pikey Dave]

Originally Posted by HDAV

Thanks last tango, they are normal can bus lights so any canbus relay could be used. Was hoping for a recommendation for one as there isn’t much obvious difference between the £8 eBay special and £30 units it’s not my car but I might end up doing the wiring or advising by video

If it’s a recentish model car, chances are that the loom is already in the rear of the vehicle & just needs a harness plugging in. Look on PF Jones.

https://www.pfjones.co.uk/towbar-wiring-kits.html

[HDAV]

Originally Posted by Pikey Dave

If it’s a recentish model car, chances are that the loom is already in the rear of the vehicle & just needs a harness plugging in. Look on PF Jones.

https://www.pfjones.co.uk/towbar-wiring-kits.html

Its not and its £130 for copycat loom from PF jones plus coding from ford.

[Pikey Dave]

Originally Posted by HDAV

Its not and its £130 for copycat loom from PF jones plus coding from ford.

Looks like your mate’s going to have to put his hand in his pocket then[emoji6]