A-4 trailer lights

[Fahrvegnugen]

Here are my golf inner tails on stock housings afaik.
One pin plug

Three pin plug

Whole housing.

After romad’s post I noticed that in daylight you can see the letters corresponding to each pin are embossed on the hosing, so if you can see the things you might not need a tester to figure it out

 

[Fahrvegnugen]

I see I mixed up the ground and tail locations and although I have a 15amp fused 12v plug, it is too high an amperage to do any good, so the mix up crisped it but did no real damage, except for that which was done to the 23 position 5 amp mini fuse! Replacing that and properly wiring the 3 pin plug fixed the tail light.
The 12v plug needs a 15amp fuse to keep from getting too hot, but the powered converter requests 10 amp protection, I'm getting about 11.5v out of the 4 flat trailer plug. I wonder if I should patch in a 10amp inline fuse before the converter.

 

[romad]

My converter uses a cigarette plug with a built in fuse but I can't remember if it is 10 or 15 amp.

Edit: Just checked and it is a 10A 32V fuse.

 

[vandermic07]

I am having issues with my 03 wagon. I have no turn signals to the trailer harness. Turn signals a working on the car but no output on the secondary connection (-) connection. Both right and left are acting up.
My meter is able to detect the current pulses on BL to 31 and BL to frame.

 

[romad]

I am having issues with my 03 wagon. I have no turn signals to the trailer harness. Turn signals a working on the car but no output on the secondary connection (-) connection. Both right and left are acting up.
My meter is able to detect the current pulses on BL to 31 and BL to frame.

Where are you taking those measurements? At the BL pin on the center bottom RF NES/BL/S/BR/31/NES RF connector of the rear taillight bulb assembly, at the center 31/BL/S connector, or at the output of the 5 to 4 wire converter?

If you are getting the meter readings at the output of the converter, then the problem is probably in the trailer wiring; if you DON'T get a reading at the converter output but DO at the connectors on the back of the car's tail light assemblies, the the problem is with the converter most likely. If I understand correctly that you don't have turn signals on BOTH of the trailer light assemblies, then I suspect the converter. What brand converter are you using between the car and trailer?

 

[vandermic07]

I think I figured it out. I wired it the same as the golf but the wagon housing doesn't have the same pins in the plug as the golf. The BL secondary connection is below the main connection. So I need a 2 prong connector to make it right.

 

[romad]

I think I figured it out. I wired it the same as the golf but the wagon housing doesn't have the same pins in the plug as the golf. The BL secondary connection is below the main connection. So I need a 2 prong connector to make it right.

Yes, you will need at least one if the problem is ONLY the Rear Light (BL) but if the problem is also with turn signal lights (S), then you'll need two of the 1J0-972-924 connectors as those have to be tapped off of BOTH tail light assemblies on the vehicle.

Edit. After re-reading this entire thread, it sounds like your tail light assemblies may be different from mine. Do yours look like these in post 58 above: https://forums.tdiclub.com/index.php?threads/a-4-trailer-lights.379375/post-5594202

or does it look like the diagram in Herm TDI's post # 1: https://forums.tdiclub.com/index.php?threads/a-4-trailer-lights.379375/post-4121790

 

[romad]

I think I figured it out. I wired it the same as the golf but the wagon housing doesn't have the same pins in the plug as the golf. The BL secondary connection is below the main connection. So I need a 2 prong connector to make it right.

I just sent you a message with a better graphic of the connections shown in Herm TDI's post. I hope you get it as I had to figure out what type of image would work with this system's messaging function.