Have now put earth connector as picture above, checked fuses and all are ok. I have put a multimeter on to test output at plugs and I only get a small feed coming out of the right hand indicator, nowhere near 12v.
so I am wonderering if the sockets themselves are faulty - do I cut wires and new sockets?
Or is the towing module faulty?
also I have been told that the towing module may need activating at the garage so the ecu then knows it’s there, not sure how accurate that information is.
This one’s got me stumped.
Ok, I'll answer the questions in sequence.
So if the earth point is in the correct place, then one can assume that's all good.
So you're on to testing the wiring at the plug, then the plug itself.
The plugs are sealed for life, the electrical connections being fully potted from the back of the plug with electrical potting compound.
This makes testing the connections at the back of the plug tricky, but not impossible. The only way is to probe through the wire PVC insulation, with a sharp probe (a sewing needle works well), then put a test light on the needle and earth, and see what happens.
All lights are powered by the towing module, with the exception of the brake lights, which are powered directly from the brake light circuit.
It possible to test the in 2 ways. First is using a suitable diagnostic test unit.
Basic home testing is also possible. The brake light circuit doesn't go through the module. The brake light are supplied through the towing harness directly from the brake light circuit. So if the brake lights work, there's a good chance the towing module isn't working correctly, or it's not getting a supply from the ignition circuit, or it's not getting the data stream from the CJB.
Do you have a picture of the module in situ, so I can see if any plugs are missing?
Can the plugs be changed, then the answer is yes, as I had to fit a new supplementary socket to mine, as it had been cut off by a previous owner.
Yes the towing module will work without telling the vehicle that it's fitted. However not programming the vehicle to say a towing module is installed prevents the towing enhancement functions from being activated when a trailer or caravan is plugged in, but all the lights work without activating the module.
