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Post by phange on Aug 13, 2024 4:56:29 GMT
2016 MK7 VW Golf R North America
MK7 OEM Rear Tails to Mk7.5 Facelift Euro Tails using Shopdap Harness and App - driver brake light does not work Problem Statement: Everything works except driver side brake light when brake pedal pressed (outer lamp). Running lights, reverse, everything else works great. Passenger brake light also works perfectly. Turn signals work. Original Settings/Setup:BCM. ODX 015001 OEM 2016 MK7 Golf R tails Halogen Changes made for this upgrade:
1. VAG 5G1-052-200-C from e-Acca 2. 5G0-998-998-AF MK7 to MK7.5 Facelift LED Tail Light Adapter Harness for MK7 from Shopdap 3. Shopdap Mk7 Facelift Euro Tail lights OBDeleven app using setting 'LED OLD BCM' Troubleshooting steps taken:1. Confirmed wiring is properly seated and locked for all connections according to printed procedure from shopdap (not attached). 2. Confirmed connections according to Shopdap video: 3. Confirmed Lasttyp21 is set to 34 LED Bremschleuten according to app and written instructions (see below attachment). 4. Confirmed integrity of connections in pin #1 outer driver side fitting (red, red, purple) 5. Confirmed integrity of connections in pin #1 outer passenger side fitting (white) Potential causes:1. Faulty wiring from Shopdap harness? 2. Faulty bulb from driver outer lamp? Could anyone give me suggestions for other coding I could try? Thanks in advance for any assistance.   |
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Post by dv52 (Australia) on Aug 13, 2024 20:47:36 GMT
Hmm.........let's start by talking about the cross wiring harness - which I suspect is the problem in this instance. The purpose of this component on these type of projects is to deal with the fact that the wire-count in the factory loom from the BCM to the car-side of the tail-light connectors is insufficient to operate the new tail-lights. This happens in the following 2 x situations on MQB platform cars like this car: - If the car was factory built with tail-lights that have incandescent lamps and new LED fittings are to be installed (of any type) - the LED tail-lights have a greater number of lamps than incandescent tail-lights. So there are insufficient wires in the factory loom
- If the car was factory built with tail-lights that have LED lamps and new "dynamic turn-signal" fittings are to be installed - the new tail-lights require a power-supply to operate the dynamic function. So, again there are insuffient wires in the factory loom.
Clearly situation 2. above applies in this instance.
Basically the cross-wiring harness joins together lamps on the tail-lights that were factory connected to separate wires and it operates these lamps "in parallel". As an example, as factory connected - the left-side and right-side Brake-lights on this car were factory connected to 2 x separate wires like this: - Left-side Brake-light is connected to a wire that is terminated on BCM pin #71, socket A
- Right-side Brake-light is connected to a wire that is terminated on BCM pin #8, socket B
With the cross-wiring harness installed, the left-side and right-side Brake lights on this car are now joined together and they are both connected to the wire that is terminated on pin #8, socket B on the BCM. The original wire to BCM pin #71, socket A is freed-up and it is used to supply power to the LED chaser circuits in the new tail-lights that provide the dynamic turn-signal function.
The reason for explaining the stuff above is because I suspect that this problem is not a coding problem. Rather, my hunch is that the fault is caused by a physical wiring issue. Your coding attachment confirms that the Brake lights on these new tail-lights operate as I describe above. This means that if the dynamic turn-signal function is operating correctly, the original wire to BCM pin #71, socket A is coded OK and it's physically connected correctly. And it also means that if the passenger side Brake light "works perfectly", the coding and physical connection to pin #8, socket B is also correct.
However, if the driver-side Brake-light is NOT working, it means that the problem is in the cross-wiring harness that joins the left/right side lamps together. If this was my car, I would eyeball the integrity of the connection on pin #1 on outer driver-side fitting (this is the Brake-light pin). Also trace and check this wire which runs to the same pin number on the passenger-side outer fitting.
Don
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Post by phange on Aug 19, 2024 17:14:13 GMT
Hello dv52, Thank you so much for your thoughtful reply. I saw your help on other posts and was looking forward to your reply on mine as well. Cheers! 1. Looks like my original 2016 MK7 golf R tail lights are halogen. Note in my original post that I selected 'LED OLD BCM' in the Shopdap OBDeleven app. Do you think this could cause a coding issue? And in extension, would this mean your situation #1 would apply instead of situation #2? I added a photo in the original post with a photo of my halogen tail lights to better illustrate the starting point. 2. Regarding your reply for situation #2:
However, if the driver-side Brake-light is NOT working, it means that the problem is in the cross-wiring harness that joins the left/right side lamps together. If this was my car, I would eyeball the integrity of the connection on pin #1 on outer driver-side fitting (this is the Brake-light pin). Also trace and check this wire which runs to the same pin number on the passenger-side outer fitting. The integrity of the THREE connections (red, red, purple) on pin #1 on outer driver-side fitting (brake light pin) are good. I took opened the tab, gently reseated/pushed the red, red, purple connections and locked it back into place.
The integrity of the ONE connection (white) on pin #1 on outer side passenger side fitting is good.
These pin #1 connections on outer driver side fitting came original from Shopdap, the harness supplier. However is it odd that it is three colored connections (red, red, purple) from pin #1 outer driver side that goes to white pin #1 on outer passenger side outer fitting? As in, do we expect a red or purple in pin #1 passenger side outer fitting?
I have traced the wire, and it looks like none of the pin #1 connections (red, red, purple) on outer driver side run to the same pin number #1 on the passenger side outer fitting, because pin number #1 on the passenger side outer fitting is a white connection only. Do we expect some of the colors to match?
Driver outer fitting: 
Passenger outer fitting:  |
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Post by dv52 (Australia) on Aug 19, 2024 22:35:05 GMT
hmm..... so my problem is that I don't have much information about NAR factory wiring looms! I suggest that you start your investigations on the mating sockets to those in your pictures, meaning the connectors on the Golf R factory wiring looms - not on the connectors on the new tail-light fittings This is my understanding the OEM tail-light connections on non NAR model Golf mk7/7.5: Clearly given your statement that this car was factory built with incandescent tail-light lamps, the appropriate set-up in this case is the upper circuits. Of course NAR incandescent tail-lights do NOT have a separate turn-signal lamp - but the brake light (combined with turn-signal on "Yankee" cars) is still terminated on pin #1!
And if I'm reading the DAP coding sheet correctly - after the coding changes: - Pin #1 on the
right left-side outer factory-connector should be +12V regardless of the ignition-switch position (this is called a "Terminal 30" voltage supply and the DAP set-up uses this wire to supply power to the LED chaser circuits in the dynamic turn-signals on the new tail-light fittings )
- Pin #1 on the
left right-side outer factory-connector should be +12V ONLY when the brake pedal is pressed.
I suggest that you start by grabbing a multi-meter and by confirming the 2 x voltage conditions above on the factory-connectors
If the voltages above are OK -then measure the voltage on the mating pin #1 on the 8 x pin connectors for the new fittings (the connectors in your pictures).
According to your words in your first post - my hunch is that you will find that pin #1 on the the driver-side (left-side) 8 x pin connector will be 0V when the brake-pedal is pressed.
If so, the problem clearly lies in the part of the cross-wiring harness that joins pin #1 on the factory-connector to pin #1 on the 8 x pin connector for the left-side tail-light fitting! Again if so, trace the voltage in the wires in the cross-wiring harness that connect to pin #1 at each point where the wire is terminated!
Don
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Post by phange on Aug 26, 2024 1:50:06 GMT
Hi Don, I did a check of your two voltage conditions, but I wasn't sure which one was pin 1 on the 4 pin factory connectors, so I tested both connector orientations, with and without braking and supplied pictures. Car engine was ON during this testing. - Pin #1 on the right-side outer factory-connector should be +12V regardless of the ignition-switch position (this is called a "Terminal 30" voltage supply and the DAP set-up uses this wire to supply power to the LED chaser circuits in the dynamic turn-signals on the new tail-light fittings )
- Pin #1 on the left-side outer factory-connector should be +12V ONLY when the brake pedal is pressed.
_  In case the voltages are OK for the factory-connectors, I tested the pin#1 voltages also for the new fittings with the engine ON:
left side: 13.89v
right side: 13.80v
If so, the problem clearly lies in the part of the cross-wiring harness that joins pin #1 on the factory-connector to pin #1 on the 8 x pin connector for the left-side tail-light fitting! Again if so, trace the voltage in the wires in the cross-wiring harness that connect to pin #1 at each point where the wire is terminated! I am not sure what it means to trace voltage, could you clarify? I’ll make an attempt after work tomorrow. Many thanks! |
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Post by dv52 (Australia) on Aug 26, 2024 5:07:13 GMT
phange : OK - The first two pictures of the four multi-meter screen photos in your 2 x attachments are the correct pin #1 positions. But, my bad - I mixed-up the car-sides in my last post. I should have said the following: - Pin #1 on the
right left-side outer factory-connector should be +12V regardless of the ignition-switch position (this is called a "Terminal 30" voltage supply and the DAP set-up uses this wire to supply power to the LED chaser circuits in the dynamic turn-signals on the new tail-light fittings ) - Pin #1 on the
left right-side outer factory-connector should be +12V ONLY when the brake pedal is pressed.
I've corrected the error in my previous post to reflect my revised words above
In respect of your Brake-light problem, the first 2 x photos of the multi-meter pictures for the right-side fitting complies with my point 2. above. This means that the correct voltage for the Brake light function appears on factory connector for the outer, right-side, tail-light fitting - being pin #1. This is a good result! This is the wiring arrangement for a "Yankee" Golf that has an OEM outer, left-side tail-light fitting with an 8 x pin connector and with dynamic turn signal - the right-side fitting has the same pin-out: If you are not familiar with the nomenclature on VW wiring diagrams, this is how it works: - Notice that the connections on the tail-light fitting above has designations like T8 /7. This means:
- T8= a connector with a Total of 8 x pin positions
- /7 = pin #7
Now, the DAP tail-light fittings on this car are definitely NOT OEM - so the pin-outs for ALL the lamps on the new fittings will NOT be the same as in my picture. For example, notice that the OEM fitting in my picture uses pin #7 for the reverse light. This is a copy of the picture that you posted earlier for the new DAP left-side fitting:
 Notice that pin #7 is vacant in your picture! This is because the DAP outer fittings do NOT have a reverse light (unlike the OEM fittings)
However, I assume that the pin-out for the DAP fittings is the same as for OEM fittings where both fittings use equivalent lamps - like the Brake-lights. Therefore, I assume that the DAP fitting uses pin #5 for the signal to the Brake-light lamp
So, I suggest that you grab the multi-meter again and measure the voltage on pin #5 of the 8 x pin DAP connector with the Brake pedal pressed and not-pressed. If the cross-wiring harness is operating correctly, the results for your ealier tests on pin #1 of the factory connector should be the same as for pin #5 of the DAP connector!
Don
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Post by phange on Aug 27, 2024 3:06:22 GMT
Hi Don Thank you for the great explanations and details. For pin #5 DAP driver outer fitting I am getting 0V for both brake pressed and not pressed. This is not the result I expected because based on what you've explained, I should be getting the ~13V, but I am getting 0V. In terms of my method, I jammed the red prong from the multimeter Into pin#5 socket as far as it could reasonably go because it’s the only way to make contact with the pin. Not sure if this is the best method. Could you advise? Cheers! 
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Post by dv52 (Australia) on Aug 27, 2024 22:55:50 GMT
As you will appreciate, I really can't say whether the meter-lead is making actual contact with the metal part of the pin on the 8 x pin connector, but the general method that you describe is correct - it's called "back-probing". There are special back-probing tools for these measurements - but using a small sewing needle inserted into the rear of the connector to make contact with the metal pins is a good/cheap alternative
Lets reset the discussion and go back to basics: as I understand, the set-up on this car for the outer tail-light fittings is like this: - The wires from the module that supplies power to the tail-light lamps terminate onto factory connectors that have 4 x pin positions
- The connector on the new tail-light fittings has 8 x pin positions
- A cross-wiring harness is used between the factory connector and the connector for the new fittings. This harness has a 4 x pin connector on one end and a 8 x pin connector at the other end for the outer fittings on each car-side
Your previous tests confirm that the Brake-light signal is OK on pin #1 on the right-side factory connector. With the harness plugged-into the factory connector- the Brake-signal should appear on pin #5 of the 8 x pin harness connector on both car-sides. And with the new tail-light connector also plugged into the harness connector, the Brake-light signal should appear on pin #5 on the tail-light connector.
Because the passenger side brake-light works, you know that the brake-light signal correctly appears on pin #5 on the passenger-side tail-light connector
If you have the harness installed AND the outer tail-light connectors unplugged on both car-sides, you should have good access to the 8 x pin harness connectors.
So, using your multi-meter, you should be able to confirm that the Brake-signal appears on pin #5 on both car-sides of the 8 x pin harness connectors. My hunch is that you will find that the correct voltages will appear on the passenger-side harness connector- but no volts will be measured on the driver-side harness connector. If so, the fault lies on the harness wires that join pin #1 on the 4 x pin right-side harness connector to pin #5 harness connectors
Don
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Post by phange on Aug 28, 2024 2:32:44 GMT
Hi Don,
Thanks for all your help. I will conclude at this time that the problem is in the harness.
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