Comparing Wiring Harness Options For A 2015 Audi A4 Premium Quattro S-Line  

Question:

Expert Reply:

Hello Ben. The Curt Powered Tail Light Converter # C59236 and the Tekonsha ZCI Harness # 119250KIT can both be used on your 2015 Audi A4 premium quattro s-line. The main difference is the Curt harness need to be hardwired, while the ZCI harness has clamps that go over the wires and does not require any cutting or splicing of the vehicles wiring harness. Generally, the ZCI harnesses are used on newer more high-end vehicles like your Audi since they are no-splice.

expert reply by: Jesse M

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Jesse M.

2/17/2026

Hey Ben, how did things go with the ZCI wiring harness on your Audi A4? Did the no-splice clamps make the setup easier than the Curt harness would have? Your update could make it easier for others choosing between these two kits.

Ben

2/17/2026

@JesseM The wiring was very simple and much easier with no permanent alteration to factory wiring than would be the case with splicing into the factory wiring. The connectors simply clip on over the existing wiring without actually splicing into the wire. However, I did experience the same issue as others have mentioned where the trailer lights remain illuminated even after the vehicle and all lighting have been switched off. To resolve this i just simply have to unplug the trailer harness connection whenever parking for extended periods so the lights do not continually stay on. Other than that, the product worked perfectly and very easy to install without having to directly splice into any of the factory wiring. With my car battery being located in the trunk under the spare tire, it made for a nicely contained setup with all connections easily accessible from the trunk area. I would recommend this kit for anyone that does not want to permanently alter the factory wiring in any way. If I change vehicles in the future, this kit can be easily removed and transfered to another vehicle without leaving any permanent alterations or spliced wiring connections behind.

Jesse M.

2/18/2026

@Ben Hey Ben, really appreciate you taking the time to lay all that out. That is exactly the big advantage of the ZCI style harness, no cutting or splicing into the factory wiring, and everything can be removed later without leaving a trace. Sounds like you did a clean install, especially with the battery tucked in the trunk area and all the connections easy to get to. Thanks for mentioning the lights staying on issue too. That can happen occasionally depending on the vehicle’s lighting system, and unplugging the trailer connector during extended parking is a simple and effective workaround. Thanks again for the detailed feedback. That kind of real-world info helps the next person know what to expect.

Ben

2/19/2026

This kit was installed on a 2015 Audi A4 Quattro