Another reason not to fit a Volvo OEM towbar........

[Rentagas]

I opted to fit a volvo tow bar to my new XC90 because I thought it would look good and would not be a problem.....despite the fact that it was more expensive than the alternatives.

I made it clear it was to to a caravan and wanted a 13 pin DIN socket with a removeable bar.

Picked up my caravan today from it's service and the ALKO ATC caravan stability system was flashing red indicating something was up! Fortunately the ALKO engineer was on site and checked it and said the problem was that it was not receiving power, which he said should come from the auxilliary supply that also supplies the fridge and charges the battery. They said they had seen this before with Volvos

So phoned Sturgess and spoke to them about it. They have had this problem before and say that the 13 pin DIN socket has an optional pin that volvo don't power in their wiring kits. This is the pin ALKO use to power the ATC. To fit one will cost extra...........

Now bearing in mind my "other" car powers the ATC with no modification and so does every other car in the caravan dealers car park this is not good

[Rentagas]

Looking at this in more detail.......................

The pins in question are pins 9 and 10

Pin 9 is a permanently connected pin from the battery the ATC uses this.
Pin 10 is the fridge supply which comes on with ignition

The ATC should be connected all the time because it self tests when plugged in and if it were not a stall would cause a self test (including applying the brakes!)

In the Volvo tow bar instructions it clearly shows that pin 9 should be powered. Only pins 11 and 12 are not used. Pin 11 is an earth and pin 12 is signalling from the trailer. Pin 13 is the ground from pin 9.

http://www.volvoclub.org.uk/pdf/Towb...ics13Pin-2.pdf

The ATC should be powered from pins 9/13 so it SHOULD work.

[keithmcc]

I had a Volvo detachable fitted to mine last October. I have had no problems with pin connections on mine - fridge and battery charging OK while towing.
I had left specific instructions on the seat of the car about the pin connections, but was told afterwards that was not necessary.

[Buck Rogers]

Hi Rentagas,

I am a bit worried about this. On my MY10 XC90 I had a Volvo bar + 13 pin electrics fitted. My current van does not have ATC, and I have no idea if Pin 9 works. As such I am just about to collect my new van, 1st time with ATC, and to save a long journey to the midlands, do you know any way to test before? or I guess it's back to the dealer.

Thanks Buck

[Rentagas]

I have just bought a multimeter from amazon to test my connector and I'll be using this to test the tow connector before my row with sturgess.

According to the Volvo fitting instructions pin 9 and 10 SHOULD be connected these are the supplies to the ATC and fridge respectively.
Similarly pin 13 should be connected which is the earth from pin 9

However in the Volvo diagram pin 11 is not connected and this is the earth from the fridge. Because the fridge takes a meaty supply this needs to be a thick 2.5mm2 wire as do the supply wires.

Pin 10 should come on with the ignition and pin 9 should be on all the time.

So it should be simple to test the current from pin 9 and 10 respectively with a multimeter with the ignition on and off.

Just to confuse things further most caravan electrics draw the charging current and internal lights from pin 9 but only when pin 10 is active via a relay.

With my caravan connected and the engine on the caravan sense voltage in 10 ( I think) but because there is no earth the fridge is off. In addition the battery does not charge and the lights don't work because there is no power from pin 9. With the ignition off the interior lights work from the caravan battery even though the car is still connected.

As far as I know there is no harm from running the caravan with no power to the ATC it just behaves as a caravan with no ATC. The only exception to this, according to several post on this and other forums, is where the ATC gets power initially and this fails during self test. Some owners have reported a weird system where they have a switch in the caravan to switch between car and caravan supplies. If this is in the wrong position the AtC will be powered at self test but when the car ignition comes on because there is no power fro pin 9 the ATC switches off with the brakes applied which can burn the brakes out as the caravan is towed.

[keithmcc]

To avoid flattening the car battery the supply at pin 10 should be governed by the alternator supply

[262coupe]

Hi Rentagas,

I have a 13pin removable towbar on my brandnew D5 exec and had the same on my V8 SE LUX. I tow a Bailey caravan with the same AL-KO ATC system you describe and have never had any problems, maybe it was just poorly installed??

[Rentagas]

Originally Posted by 262coupe

Hi Rentagas,

I have a 13pin removable towbar on my brandnew D5 exec and had the same on my V8 SE LUX. I tow a Bailey caravan with the same AL-KO ATC system you describe and have never had any problems, maybe it was just poorly installed??

Yes maybe it is..........we'll see what they say. Do you have a fridge supply?

[Rentagas]

Well multimeter arrived and............

Pin 9 (which should be a permanent feed) is showing 0.6V!
Pin 10 switches on with the engine and shows 13+V (correctly)
(both relative to pin 3)

Pin 11 which should be an earth but volvo don't connect is isolated
Pin 12 which should be isolated and is not used is an earth

Sturgess Volvo of Leicester......................

[Sunken]

Spoke to hubby about this,he is an independent towbar fitter and has been for 15 years.He said it could be a number of things,earthing problem,relay problem,socket not working.His advice is to go to a local independent.He's fit a lot of bars to xc90's lately,thats why I decided to buy one and not one has ever come back to him.Hope this has helped a bit.