I've recently been given a trailer which has 7-pin electrics. I've got a 7 to 13-pin adaptor to plug into the car, which is equipped with OEM electrics and towbar. 

 

When I've previously borrowed a neighbours 13-pin equipped trailer, when it was plugged in, the car recognised as such and does it's electronic magic with regards to stability, etc, including disabling the reversing sensors when reversing.

 

With the 7-pin trailer, using the adaptor, I don't get the same thing. Any ideas why this could be and if there is any easy fix. It surely can't be down to just changing the 7-pin plug for a 13-pin one? I'll add that the trailer doesn't have fog or reversing lights on it, just the normal indicator, numberplate and brake lights.

I thought that there was a microswitch in the 13pin socket which worked when the 13 pin plug was inserted and told the electrics that a trailer was being used. Perhaps your adaptor does not trip the microswitch. Could you not just replace the 7 pin plug on the trailer with a 13 pin plug?

11 minutes ago, Liger1956 said:

I thought that there was a microswitch in the 13pin socket which worked when the 13 pin plug was inserted and told the electrics that a trailer was being used. Perhaps your adaptor does not trip the microswitch. Could you not just replace the 7 pin plug on the trailer with a 13 pin plug?

 

I could, but as I don't know for sure what triggers the CANBUS to know that a trailer is attached, I don't want to just re-wire a plug in hope.

I previously towed my 7 pin electrics trailer with my wife's Tiguan fitted with 13 pin electrics, using a 7 pin adapter.  The car recognised that the trailer was there as evidenced by the display on the screen when selecting reverse and the alarm sounding if the trailer was unplugged when the car was locked.   

My wife now has a Karoq 190 TDI with 7 pin dedicated electrics and I've purchased a 2016 Yeti 150 TDI to which I've had fitted a tow bar and 7 pin dedicated electrics.  Again, both cars recognise when there is a trailer attached.  It therefore seems unlikely that the issue you're experiencing is caused by using an adapter per se.  It might be worth trying anothed adapter to see if it makes a difference. 

Just now, Schtum said:

I previously towed my 7 pin electrics trailer with my wife's Tiguan fitted with 13 pin electrics, using a 7 pin adapter.  The car recognised that the trailer was there as evidenced by the display on the screen when selecting reverse and the alarm sounding if the trailer was unplugged when the car was locked.   

My wife now has a Karoq 190 TDI with 7 pin dedicated electrics and I've purchased a 2016 Yeti 150 TDI to which I've had fitted a tow bar and 7 pin dedicated electrics.  Again, both cars recognise when there is a trailer attached.  It therefore seems unlikely that the issue you're experiencing is caused by using an adapter per se.  It might be worth trying anothed adapter to see if it makes a difference. 

Thanks, it may well be the adaptor in that case.

I think on the 13 pin socket 2 of the pins on the trailer plug are linked to form a circuit telling the towing module that the trailer is connected, this may be specific to the vehicle and in which case the adaptors wont have the link but it would be easy to modify.

 

Some Googling will reveal what pins to link, it may indeed be the standard configuration.

Bit late now, but this might help for people searching in future:
According to https://en.wikipedia.org/wiki/ISO_standards_for_trailer_connectors the 2002 version ISO 11446 specified that pin 12 was to be used for trailer detection, by linking it to ground on pin 3. This function was apparently removed from the standard in 2004, which reserved pin 12 for future allocation.
If the Octavia is designed according to the superseded version of the standard, it might be trying to use pin 12 for detection, while a modern adaptor would not connect it. Therefore looping pin12 to pin 3 might help and shouldn't cause any harm.

Edited 7 June, 20205 yr by Rodge

On 25/05/2020 at 20:35, wg100 said:

Thanks, it may well be the adaptor in that case.

Is it an OEM adaptor? 

 

My OEM works perfectly 

 

Try not being so cheap Will🤣🤣🤣

1 hour ago, themanwithnoaim said:

Is it an OEM adaptor? 

 

My OEM works perfectly 

 

Try not being so cheap Will🤣🤣🤣

Not an OEM adaptor, but in my defence, it is all working correctly now! Must have a been a poor connection initially.