Tow Bar Wiring without special harness

[NI_Volvo_Nut]

https://www.amazon.co.uk/Thule-75905...bmodelId=16082

This is the last one I got for a 2004 V70 (03MY) I can't see why XC90 would be different but I haven't done a towbar on one.

Warninglight I think has a bit of knowledge about them, maybe drop him a pm

[Simon Jones]

I don't have an XC90, but have had 3x XC70's of different types. Up to facelift in 2004/5 it was a plug & play connection into a grey socket in the spare wheel well. From then to 2007/8, you needed a separate TRM (trailer module) that plugs into Trailer socket on REM. From 2007 onwards, you still need a TRM but it plugs in under the boot floor. That's probably of minimal relevance to you other than so illustrate that the wiring methods change over a production run so you need to be 100% sure which part is required for your particular model.

[SweetAs]

Eurgh...nothing is simple lol.

The spare wheel is secured externally so there is no wheel well to speak of. I've checked everything I can and the only grey plug is one with 12 wires under the drivers side light cluster. They do match up with the ones in the 7 core cable but there is also 3 green wires and a couple of others.

I double checked with a couple of tow bar companies and they said that universal spliced electrics should be fine as long as I am using a relay, which I have. They couldn't however advise me of a specific loom to splice into.

I fully understand everyone's comments about not doing it but I can't even find a part number of a plug and play loom to buy so seeing as I have the parts and I am fully aware of the risks however I want to see if it can be done safely. If there is a special plug which I need to find then surely that would be the best place to splice into? Happy to solder connections instead of the scotch things, that's not an issue.

OK so, is there anyone who has successfully spliced wires in for a universal tow bar? There must be people who have managed it as the tow bar companies I spoke to don't use the volvo loom. We are due to go camping on Monday for a week and would be gutted to put the holiday on hold for a few days so thanks for the help!

[SwissXC90]

Use the wiring diagram
Tap into existing wires directly if you don't care about the bulb warning messages not working due to extra bulbs.
Or use relays if you want to decouple the trailer load from the taillamp load.

We're talking light bulbs here, not rocket science!

[SweetAs]

Cheers for the reply Swiss.

Your right, it's not rocket science. I think that maybe the entire day and night spent at the local beer festival yesterday could have screwed with my thought processes today lol.

I'm feeling a whole world better now so I have a plan :-D

First off I'm going to stop over thinking it and work logically through what I need to do. I'm going to use the bypass/relay and pick up some extra wiring/fuses tomorrow so that I can crack on with it.

I'll drop an update tomorrow or Sunday I get the chance and let you all know how I got on.

Thanks again for all of the help!

[Father Ted]

It is the socket / plug on driver's side at the rear.
Here is a sheet I put together based on the document covering V70 and XC90 , along with the wiring colours.

Along with the colours on the spread sheet, the following make up the remaining pins.
Blue(small) Reverse
Large Red Permanent +12v (I haven't got this to work yet.
Large Blue Switched 12v (fridge)

You will need 3 good grounds, I used a bolt into the body near to the cable entry.

(If the uploads don't work, let me know and I'll email you the documents.If I get chance tomorrow, I will take photos of mine.)

[SweetAs]

Father Ted.....I love you!!! Haha apologies as I don't know you but thanks for the info.

Apologies for the late update but I only got back last night.

For anyone who is bothered.....

So mine is the early 2003/2004 model which means no specific wiring loom, not one that I could find anyway. This meant I needed to follow Father Teds info above and managed to get it working. I picked up a tester light and checked each wire, his diagrams were perfect! I ended up scotch locking the wires as it went down to the wire but those will be swapped out for soldered joints this week now I have the time.

I used a TEB7AS relay I picked up from amazon for under £20. A world cheaper than anywhere else I could find who would deliver it in time. Hooked it up and away I went.

Again, thank you "Father Ted". I had been massively over thinking it and needed a bit of a kick in the arse to stop me from stressing so I could crack on.

If anyone else is thinking of doing it, definitely give it ago but it all depends on the year of your vehicle!

[jamessinclair]

hi does anybody know what kind of wiring system is in a volvo xc90 d5 2008

[gmonag]

If you are fitting a towbar, the best option for the wiring is undoudtedly genuine Volvo. It costs the same (even less) than unniversal wiring and is plug-and-play. Everything will work as it should - simples.

[S60D5-185]

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