Rear tail light wiring?
Thread Starter
AudiWorld Junior Member
Joined: Feb 2024
Posts: 5
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Rear tail light wiring?
Greetings, first post so if this is wrong spot, please redirect.
2021 Q7 - Bought a wiring kit for towing as it didn’t come with one. I found one on etrailer thats ZCI, which is great because I don’t need to splice into the wires. I have it all installed, the only snag is this - the video for a 2019 Q7 has 4 wires going into the right tail light, mine has 6. I have found the brake, left turn and running lights, they all work great. However when I hit the right turn, the four ways come on, so obviously something is off.
ive looked everywhere - does anyone know where i can find a diagram showing what each wire represents for the right rear tail light?
thanks
2021 Q7 - Bought a wiring kit for towing as it didn’t come with one. I found one on etrailer thats ZCI, which is great because I don’t need to splice into the wires. I have it all installed, the only snag is this - the video for a 2019 Q7 has 4 wires going into the right tail light, mine has 6. I have found the brake, left turn and running lights, they all work great. However when I hit the right turn, the four ways come on, so obviously something is off.
ive looked everywhere - does anyone know where i can find a diagram showing what each wire represents for the right rear tail light?
thanks
AudiWorld Super User
Joined: Jan 2021
Posts: 4,566
Likes: 1,456
From: USA - NM
Yup, this is the wrong forum; look at the top or the Q7 selections/descriptions where shows you the chassis and dates of production, etc.
You need the MK II Q7 Forum for the 4M chassis. Too bad you got the aftermarket harness, as that means your towing won't integrate with the car's systems directly, and you'll find out what that means. Most owners adding tow receiver for actual towing use just buy a used harness/lighting control module from a parts recycler (junk yard) online, coupled with a good class IV aftermarket or the OE (recycled) tow receiver. If you plan on very basic tow use it'll probably be fine...probably.
Definitely consider what you want/need to tow in the future and let that be your guide to how you build it out. The OE wiring setup allows you to integrate a braking controller for heavier, multi-axle trailers/RVs, etc, and also provides a 12V feed, as well. The clip-on or spliced aftermarket trailer light harnesses do not, and as mentioned does not let the car know you are towing, so all the benefits your Q7 brings to the table are basically left on the table unused.
Good luck, be safe!
Oh, and by the way, the bolts that hold on the rear bumper mount are single-use, torque-to-yield bolts and will snap off if reused, so be sure to use only new hardware to affix the tow receiver to the car.
You need the MK II Q7 Forum for the 4M chassis. Too bad you got the aftermarket harness, as that means your towing won't integrate with the car's systems directly, and you'll find out what that means. Most owners adding tow receiver for actual towing use just buy a used harness/lighting control module from a parts recycler (junk yard) online, coupled with a good class IV aftermarket or the OE (recycled) tow receiver. If you plan on very basic tow use it'll probably be fine...probably.
Definitely consider what you want/need to tow in the future and let that be your guide to how you build it out. The OE wiring setup allows you to integrate a braking controller for heavier, multi-axle trailers/RVs, etc, and also provides a 12V feed, as well. The clip-on or spliced aftermarket trailer light harnesses do not, and as mentioned does not let the car know you are towing, so all the benefits your Q7 brings to the table are basically left on the table unused.Good luck, be safe!
Oh, and by the way, the bolts that hold on the rear bumper mount are single-use, torque-to-yield bolts and will snap off if reused, so be sure to use only new hardware to affix the tow receiver to the car.
Last edited by '10Q7TDI_Prestige'; Jul 4, 2025 at 01:02 PM.
Thread Starter
AudiWorld Junior Member
Joined: Feb 2024
Posts: 5
Likes: 1
Yup, this is the wrong forum; look at the top or the Q7 selections/descriptions where shows you the chassis and dates of production, etc.
You need the MK II Q7 Forum for the 4M chassis. Too bad you got the aftermarket harness, as that means your towing won't integrate with the car's systems directly, and you'll find out what that means. Most owners adding tow receiver for actual towing use just buy a used harness/lighting control module from a parts recycler (junk yard) online, coupled with a good class IV aftermarket or the OE (recycled) tow receiver. If you plan on very basic tow use it'll probably be fine...probably. Definitely consider what you want/need to tow in the future and let that be your guide to how you build it out. The OE wiring setup allows you to integrate a braking controller for heavier, multi-axle trailers/RVs, etc, and also provides a 12V feed, as well. The clip-on or spliced aftermarket trailer light harnesses do not, and as mentioned does not let the car know you are towing, so all the benefits your Q7 brings to the table are basically left on the table unused.
Good luck, be safe!
Oh, and by the way, the bolts that hold on the rear bumper mount are single-use, torque-to-yield bolts and will snap off if reused, so be sure to use only new hardware to affix the tow receiver to the car.
You need the MK II Q7 Forum for the 4M chassis. Too bad you got the aftermarket harness, as that means your towing won't integrate with the car's systems directly, and you'll find out what that means. Most owners adding tow receiver for actual towing use just buy a used harness/lighting control module from a parts recycler (junk yard) online, coupled with a good class IV aftermarket or the OE (recycled) tow receiver. If you plan on very basic tow use it'll probably be fine...probably.
Definitely consider what you want/need to tow in the future and let that be your guide to how you build it out. The OE wiring setup allows you to integrate a braking controller for heavier, multi-axle trailers/RVs, etc, and also provides a 12V feed, as well. The clip-on or spliced aftermarket trailer light harnesses do not, and as mentioned does not let the car know you are towing, so all the benefits your Q7 brings to the table are basically left on the table unused.Good luck, be safe!
Oh, and by the way, the bolts that hold on the rear bumper mount are single-use, torque-to-yield bolts and will snap off if reused, so be sure to use only new hardware to affix the tow receiver to the car.
but back to the original question - does anyone know where I can find a wiring diagram for the Rear right tail light harness.
AudiWorld Super User
Joined: Jan 2021
Posts: 4,566
Likes: 1,456
From: USA - NM
apologies for the wrong spot. Understanding I can’t go back in time and I’m using this to tow a lawnmower a few times a year - I think it’ll work fine.
but back to the original question - does anyone know where I can find a wiring diagram for the Rear right tail light harness.
but back to the original question - does anyone know where I can find a wiring diagram for the Rear right tail light harness.
https://cardiagn.com/audi/audi-q7/
Last edited by '10Q7TDI_Prestige'; Jul 4, 2025 at 02:28 PM.
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