Tow Bar Wiring without special harness

[Harley Dave]

+ another 1....

Cheers

Dave

[gingerbiscuit69]

reviving an old thread, just installed onto a 2005 facelift v70. It had no module or loom fitted at all (as is the way with 2005 models, you only got factory options fitted, nothing else).

I refused to spend £120 on a module and wiring loom etc. I do a full light check each time i tow regardless, so all features are fair irrelevant. I have also installed an indicator buzzer but is switched, so only active when getting an MOT etc, they're incredibly annoying!! Not that any MOT centers seem to test them even though they should now.

you need is a bypass relay kit to safely tap into the existing wiring. It uses the electric signal to the existing lamp to switch a relay and power the trailer lights (relay gets its own +ve feed), meaning the car won't detect your trailer etc. My 7pin set with all cable, fuse holder, crimps etc etc was £20. Job done.

I will write a guide into a new thread with pictures for anyone who maybe interested in the future. Seems one person said it cannot be done, so all the other forum experts repeat it and like magic its become gospel.

[gmonag]

Seems one person said it cannot be done, so all the other forum experts repeat it and like magic its become gospel.

Actually, no.
You are just plain wrong. Genuine wiring loom and module £97.20, plug and play:

https://www.volvopartshop.com/13-pin...oaAsU3EALw_wcB

Cheapest universal kit on eBay £94:

https://www.ebay.co.uk/itm/13-Pin-To...QAAOSwhEteEw9O

Then you have to "tap into existing wiring" (not easy at all) and it still does not work as well as the genuine article!

No contest

[gingerbiscuit69]

actually no, i'm not plain wrong. As i just explained, i have no wish to have the official module, having the little blinker on the dash isn't worth £100 to me. I just want a bog standard 7pin connector on the rear which operates trailer lights. I am no purist, and i'm certainly not spending that kind of money on a 15 year old vehicle!!

Splicing into the loom isn't really difficult at all either, not for anyone confident at doing relatively basic electrical work on a vehicle.

I'll write up a guide when i get a chance, then people can make their own minds up. For those who just want to get the job done, they will surely appreciate it.

[gingerbiscuit69]

Guide posted here. Worked perfectly, took about an hour to wire. Is a safe universal method suitable for nearly all vehicles, as done by most towbar fitters.

https://www.volvoforums.org.uk/showt...63#post2626663

[Dastardly Diesel]

The money saved wont seem quite so good if it ever catches fire and the insurers engineers notice that a non approved method of towbar wiring was employed, whether that was the cause or not.

XC90s are big, complex, and expensive SUVs. If you can't afford to run or accessorise one properly then it's not the car for you.

[gingerbiscuit69]

I'm sorry DD but you're coming across as a really miserable anorak. Such snobbery.

This IS how you do it for any vehicle without modules, and how most towbar centres/auto electricians would do it. I'll leave it at that, you clearly have made your mind up.

[SwissXC90]

Originally Posted by gingerbiscuit69

I'm sorry DD but you're coming across as a really miserable anorak. Such snobbery.

Wow. Forum Rage.


My view is the same as DastardlyDiesel, but then, I am an engineer and appreciate well designed components that are highly reliable, fully documented, perfectly integrated, and supported by a global network of spare parts availability.
And in this case, very reasonably priced.

Whilst you may think the end function is the same, I see what happens behind the scene and would select a properly engineered solution over a DIY approach any time.

Example:
My rear fog lamp, which I use multiple times a year in really foggy conditions, will not be reflected to oncoming traffic by the white wall of my trailer, as the system automatically deactivates the vehicle rear fog lamp when the trailer is connected.
That is an example of a well thought out design, properly engineered and implemented.

Another example:
I am reminded of a connected trailer by the flashing trailer light in the instrument cluster when indicating.

You may see no value in all these functions and features and may not care to use them or pay for them.
I, and undoubtedly others, do see value.

[S60D5-185]

I've personally fitted towbars with 13pn electrics to my last 3 Volvos.

On each and every occasion I have used a dedicated Volvo harness and module which is simply plug and play.

Price wise I honestly think that the quality of the supplied Kit makes it pretty good value for money and I know that it will be error free.

I'm not having a go here at all Gingerbiscuit simply stating that this is my view on the matter.

If your set up is working fine and you're happy with it then so be it.

[Moose Test]

Originally Posted by SwissXC90

Wow. Forum Rage.

The thing about forums is, by definition, they attract those of us with a keen interest and passion for their topic.

Nevertheless, it would do us all well to remember that there's a fine line between offering up our experience and opinions for the benefit of others, as opposed to browbeating them into submission with it.

I think the former approach makes for a far richer and more useful forum for all of us.