landyfreelander
Member
my earth is fine and the red/blue is okay, I'm just wondering because I don't know what else I could be but can it be spliced straight off the rear lights or what they cause a lot of problems?
iv tested two modules and still getting nothing the wiring from the module to the plug for the trailer have been tested and they are all fine, so that says its from the car to the module which is the problem.
the black and blue wire is meant to turn the relay on but that does nothing, the relay is fine as its been tested and can hear it switching.
Nodge68
Well-Known Member
It's almost like the CAN bus isn't sending the data.
It sounds like it needs a diagnostic read, but you can do a basic check on the CAN bus yourself. If you have a digital multi-meter, you can measure the resistance of the 2 CAN wires in relationship to each other. They should have a termination resistor which should have a resistance of about 100 Ohms. I believe the CAN data bus for the trailer module starts at the Ipack, which is where the terminating resistor is located.
In answer to the question about direct connection to the vehicle electrical system.
It's possible and has been done, but I've also heard of reports that the extra load on the drive FETs (all lights are driven by FETs) causing them to fail, which means a replacement CJB is needed to solve the problem caused.
Me I'd get the trailer module doing what it should, but mine was easy and worked straight out the box.
It sounds like it needs a diagnostic read, but you can do a basic check on the CAN bus yourself. If you have a digital multi-meter, you can measure the resistance of the 2 CAN wires in relationship to each other. They should have a termination resistor which should have a resistance of about 100 Ohms. I believe the CAN data bus for the trailer module starts at the Ipack, which is where the terminating resistor is located.
In answer to the question about direct connection to the vehicle electrical system.
It's possible and has been done, but I've also heard of reports that the extra load on the drive FETs (all lights are driven by FETs) causing them to fail, which means a replacement CJB is needed to solve the problem caused.
Me I'd get the trailer module doing what it should, but mine was easy and worked straight out the box.
landyfreelander
Member
how and where do you test the CAN then?
Nodge68
Well-Known Member
If you have a digital multi-meter, you can measure the resistance of the 2 CAN wires in relationship to each other. They should have a termination resistor which should have a resistance of about 100 Ohms, so measure across the thin violet/orange and grey/orange wires to see what the resistance is. If it's about 100 Ohms, then the CAN is at least terminated at the other end.
If there's no resistance, then there's an issue with the CAN which will stop the trailer module from working.
