Volvo XC60 towing electrics issues

Posted on 05/08/2020 20:01 by lornalou1

This must be one of the most asked questions about Volvo electrics. I know this sites search engine is not to good but have you done a search just to see if answers are out there. Not much help I know. 

Posted on 05/08/2020 21:26 by EmilysDad

the usual question asked is why the fridge & battery charging don't work, your problem seems to be more hit & miss which would suggest to me either iffy connections in the plug &/or socket of the car or caravan or maybe where the 12v supplies in the car are taken from. Have you a friend or  neighbour with a known to work 13 pin socket on their car that you could try on your caravan to narrow the fault to either car or caravan?

Posted on 06/08/2020 09:47 by jptmail

Thanks, I have the caravan has just been serviced and electrics we’re fine, so pretty sure it’s car side. Modern electrics and older caravan. The caravan used to have the twin electrics but was upgraded to 13 pin socket and worked fine with last 2 towcars 🤷🏻‍♂️

Posted on 06/08/2020 20:11 by asda160

As a fellow Volvo owner who frequents the Volvo UK owners forum I have not seen such an issue raised as suggested by "lornalou1" nor does a search of the Volvo forum raise such a repeated issue.

You say the wiring is dedicated. Genuine Volvo or aftermarket ?

If it's the former, did the fitter get the dealer to upgrade the software so the trailer module communicates with the car?

A simple test with a multimeter into pin 8 of the car socket (pink wire)and to earth pin 3 (white wire) will clarify if the reverse light function is live all the time when reverse is selected or if it is sporadic, ie bad connection between car and wiring or fault on the towing module.

If you get the latter then it would appear you've paid good money for a product that doesn't work as it should, so go back and politely exercise your consumer rights.

If it shows as working via the multimeter then is time to check the caravan socket. Just because it was serviced don't assume there isn't an issue there. A loose or corroded connection can happen at any point.

Car electrickery can be a fickle beast and more so with a complicated car such as a Volvo which has circa 10 computers to monitor individual components.

 

Posted on 06/08/2020 21:07 by jptmail

Today I discovered that having 2 reversing lights caused the issue. Took one out and everything is perfect. Now got to work out how to get both working, possibly lower wattage bulbs, or LED. No, the software hasn’t been updated by Volvo but seems to be ok. That’ll be another discussion!...

Posted on 06/08/2020 21:07 by jptmail

Today I discovered that having 2 reversing lights caused the issue. Took one out and everything is perfect. Now got to work out how to get both working, possibly lower wattage bulbs, or LED. No, the software hasn’t been updated by Volvo but seems to be ok. That’ll be another discussion!...

Posted on 06/08/2020 22:28 by asda160

Ah, so it is a current draw thing. 

Thanks for updating, so many don't. Will be useful to others in the future. 

I've heard of this for fog lights on a caravan.

I suspect the car lighting control module(LCM) expects to detect no more than 42w current draw of the cars own bulbs and when it detects over this with another 42w of caravan bulb it thinks there's a fault and shuts down. 

If you have access to a code reader or better still Vida, Volvo diagnostic system you may have fault codes logged in the LCM

This would suggest that the towbar wiring fitted whilst vehicle specific is not Volvo OE, hence why there was no trip to dealer for software. 

Sounds like you may need canbus compatible led bulbs to lower the amp draw.

A good place to ask for help is here Volvo forum