Towbar wiring

[Metallo]

Hi All,

My 940 is an Estate, B200FT from 1997.

I am about to buy a trailer hitch, and I started to look at the schematics to figure out how to connect the lights.

I was pleased to discover that there is a pre-wired connector on the back of the car, on the driver's side. The connector is marked as D5 in the schematic, and all the wiring colors match.



I live in Canada (but my car was purchased in Italy in 1997), and the small trailers here have only 4 poles, like this one:



I have read lots of stories online about buying powered adapters, relays, etc., and I wonder:

If my car is pre-wired, do I need to be worried about the above issues, including the bulb failure light that seems to be very popular?

Since it is pre-wired, I would assume Volvo has already taken care of those issues, and I only need to find a way to connect the 10-pin connector to the trailer.

What am I missing?

I looked on the internet and I could not find an adapter from 10 pins to 4 pins or 4-ways as they call them here.

I am sure there is something I am missing in between, which is why I am asking for help.

It is my first time I have had to deal with a trailer, so apologies if I am asking the obvious.

Thank you!
Alessandro

[S60inFrance]

I don't know the specifics of your car, but I fitted a towbar to my S60 and the principle is the same. Personally, I would buy an electronic module to go between the cars wiring and the trailer just to be on the safe side. They are not expensive and all kits I looked at included one (European).

Then, you just need to identify each wire in the loom and connect up the corresponding wire for the trailer. Not knowing your car I don't know if you can buy a plug that goes into the existing plug that you have pictured, but if not it's easy to splice in.

Good luck 👍

[Metallo]

Originally Posted by S60inFrance

I don't know the specifics of your car, but I fitted a towbar to my S60 and the principle is the same. Personally, I would buy an electronic module to go between the cars wiring and the trailer just to be on the safe side. They are not expensive and all kits I looked at included one (European).

Then, you just need to identify each wire in the loom and connect up the corresponding wire for the trailer. Not knowing your car I don't know if you can buy a plug that goes into the existing plug that you have pictured, but if not it's easy to splice in.

Good luck 👍

Yes, I will buy a powered converter which will convert 3-wire EU vehicle electrical system to standard 2-wire NA trailer wiring.

Thank you,
Alessandro

[Offgrid]

I'm a bit confused. I thought that a primary towing connector had 7 pins, which would seem to fit in with the manufacturer's connector shown above. I don't see how you can get away with just 4.

Out of interest, does the 740 have an onboard connector block? the socket on the Hoe has no power, and as the brass fittings look green, I am going to replace it with a new one. I could replace the wiring as well if there is a convenient block in the body of the car ( 740 estate).

[Rversteeg]

In Europe we have seperate pins for brake and indicator lights, as well as seperate pins for OS and NS rear lights.
European trailer connectors used to have 7 poles, which left only one pin for accessories (often 12V acc feed). With the latest requirements for fog lights and reversing lights, the 7 pole connectors are more and more replaced by 13 pole ones.
In the US the brake lights appear to have been combined with the indicator lights, without the need for seperate OS/NS rear lights, fog light and reversing light, so a 4 pole is sufficient.
On the Volvo D5 connector, you can probably not simply combine the wires of the indicator connection with a rear lights. Braking would result in lighting up of both vehicle instrument panel turn indicators and indicating results in the simultaneously blinking of the vehicle brake lights.
Easiest solution would be an adapter. Most adapters work from US to EU, but this is one of the few that works vice versa:
https://www.ebay.ca/itm/383722475024...6BRNE1KPNMTAC3
You can either wire the D5 connector to 7 pole connector and use this adapter, or cut the wires of the adapter and connect them directly to the appropriate D5 pins.