Factory towbar wiring packed up
 

Yet another one step backwards whilst taking two forwards.

I removed the factory-fitted (ugly) towbar crossmember in favour of a Witter swan-neck detachable one which I've had for some time. It went well and it looks so much better, plus I don't crack my shins any more at the tailgate.

The car's wired with the black and grey sockets but as I won't ever be using the grey one, I cut that and individually insulated the seven ends before double-insulating them all & cable-tying them to the crossmember behind the bumper. I also severed the black cable from the old socket and wired it back into a new one on the Witter bar. I carefully checked that everything was functioning correctly using a trailer socket connector before starting the job, and it was. After wiring the new socket, I checked again and nothing was working. There is no power getting to any relevant socket pin but the earth pin works.

The wiring comes out of the left-side chassis leg and appears to be properly wired elsewhere other than the usual rear corners (don't know where though). The car was sleeping when I cut both cables and worked on the socket, but might I have caused an issue?

Dougie.

Blown a fuse?

Perhaps a silly question, have you tested with the engine running?

macafee2

At least the running lights and both indicators ( hazards ) should work with ignition off !


I wonder how he tested to see that the earth was OK ?

If a new earth was created between the socket and the towbar is there a good earth between the towbar and the rest of the car?

At a guess, either a shared earth or a shared live to the wires you snipped.

I don't believe one fuse would stop all live feeds?
No. I tested the hazards & sidelights feeds with the plug-in tester and then the meter.
I ran a live taillight feed from the rear of the cluster to the meter and earthed the meter through the wired (white) pin3 on the socket.
I removed the original crossmember from the towbar chassis leg components & bolted back the replacement so I'm confident the crossmember is healthily earthed. I don't know where the socket is earthed to as the 7-pin cable disappears into the nearside chassis box section towards the front.
Not sure what you mean by shared live as each component has its own live feed e.g. left/right indicator, left/right taillight etc.? And the earth is normally shared with all lives on the socket?

Dougie.

" I ran a live taillight feed from the rear of the cluster to the meter and earthed the meter through the wired (white) pin3 on the socket.


It may show as a good earth circuit on a DVM ( eventually back to bat neg ) with no load, the load applied by a DVM is negligible, but when a load is applied, bulb, there may be a poor connection via corrosion etc that won't pass the current required.

Then you will be wrong!



Trailer road lights, fridge leisure battery charge and the fancy BMW canbus electronic gubbins for trailer lamp failure, is all normally powered from a fuse in the engine compartment fuse box - if it has been wired the way Rover intended.



From that fuse a thick cable goes through to just behind the glove box and is left there, until someone adds towing components and extends that to the rear.



That supply and fuse is a permanent live, so if you cut anything at the sockets at the rear, chances are you have blown that fuse.

I have never had difficulty in being wrong when it's pointed out correctly!:D Thank you for that. I shall research and hopefully find.

Dougie.

Everybody loves a happy ending.:D

Rave showed that the factory-fitted towbar ECU should have been fitted behind the rear left-side trim in the "boot" along with a fuse. I pulled the back of the car apart this afternoon and found.... a DIY arrangement with 6-way relays and buzzers obviously fitted by Scotchloks R Us™ :rolleyes: and not the factory. However, got that sorted out and tidied, saw a phat blue power wire heading for the front of car, tracked it to behind the passenger footwell kick panel, where lo and behold, there was a 15A dud fuse waiting to be changed.:}

So if I'd not made the mistake of not checking first for a permanent live feed before chopping the 12S socket wires, I'd never have found out how to dismantle the interior rear panels (those luggage anchors :rolleyes:) nor would I have known how my towbar wiring had been put together in the car. If you're lucky, you live and learn.

Thanks again for the input. Always appreciated.

Dougie.