850 wiring....again

[Trevor_Smith]

Hi there,
First time posting.
I recently bought an N reg 850 estate with towbar fitted.
Tried the trailer,no joy with lights.Investigated the back and found the cable from the socket was carefully rolled up into an unconnected loop.Turns out that the previous owner had never needed to tow anything .
Any recommendations for the bits and bobs needed.

Many thanks in advance,
Trevor

[Fibre]

I had a wonderful N reg 850 2.5 saloon [Red] and it was a very comfortable tow car -- both from the towing and the comfort of the driver etc.

Unfortunately I did have a problem with the electrics
-- but didn't find out for three years when I went to change my caravan
-- and certain things didn't work.
-- Being new to caravaning I had thought with the first van "thats how things were"

I had had the tow bar and the electrics fitted by a Volvo dealer Grrr!
-- so I took the car back and they said it was OK..

Eventually I took it to a specialist Auto-Electrician Tuning engineers
-- who found -- after testing that the tow bar had never been wired up correctly
-- they installed a couple of new wires and suddenly every thing worked on my caravan..

Needless to say with my new S60- D5 [2006] [again Passion Red]
-- I straight way took it to them and had it checked
-- and YES they found similar mistakes..

My advice would be to have it checked out by a specialist
-- not necessarily a "tow bar fitter" as The local Volvo dealer uses a local fitter
-- but someone who understands modern car electronics.

Maurice

[rallysteve]

If your handy with a soldering iron and you have got the wiring diagram in the haynes manual then its easy enough. All you need is a relay bypass unit, halford do a Ring one which is easy to wire in if a little pricey, they are common enough though.

Just find the right wires in the boot (LHS towards the tailgate) and solder all the signal wires to the corresponding light wires.

In my own 95' 855 I used the feed for the multi-changer and aerial to provide the voltage supply needed.

Doing it all properly with soldered joints it took me an hour or so.

Let me know if you need any more info

Steve

[myshed]

Trevor, As Steve says, it's easy enough; you don't need to solder, although some professionals might argue this is the most reliable method, but you will need something like the Haynes manual to identify the car's lighting system wiring.
What you need is a Smart relay - yes, Halfords do sell the Ring brand, but at about £40 it is not the cheapest, so why not try places like ---bay, Towequipe, and your local trailer/Indespension centre?
The way it works is to "listen" to the lighting circuit, then take power direct from the battery to power the trailer lights, so the bulb-failure system is not compromised. Steve says he has taken his power from the Radio Antenna Booster (below the passenger side boot window in the estate), but I would suggest not to for several reasons - it would be easy to overload this circuit, for example, driving at night, braking with indicator on! If this circuit blows, you will have NO trailer lights and a very quiet radio, or lots of "white noise". Secondly, you may well find you get interference to the radio signal, and if you do connect an autochanger, you will get some funny effects whilst playing CD's. I know it's a pain, but the preferred power take-off is direct from the battery through an in-line fuse located at the battery take-off - it can be a bit challenging threading the cable through the car, though. I would also suggest while you are at it, taking a second heavier cable through (with its own fuse) to power the trailer's supplementary socket.

Hope this helps