Troubleshooting Tekonsha ZCI Trailer Wiring Harness Turn Signal Issue on 2017 Audi Q7

Updated 05/31/2019 | Published 05/29/2019

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Question:

My car 2017 Audi Q7 . Im install on the car hitch and ZCI zero contact module #CQT119251... Evrything works correctly except turns signals.... Right turn signal is working fine but when you turn on the left turn signal the two sides right and left flash ??? let me know please what is the problem ??? Thank you in advance.

asked by: Andrew

Expert Reply:

We need to determine if the issue is on the vehicle side or the trailer side, so first disconnect the trailer and then use a circuit tester like # PTW2992 or the one that came with your ZCI Circuit Protected Vehicle Wiring Harness # 119250KIT. If the functions don't work correctly for each pin like in the video then you will want to go back to your sensor connections and retest them. You also want to make sure the ground ring terminal is connected bare metal to metal and some sand paper may be needed for that clean connection.

If the issue is not on the vehicle side, then you will want to check the ground connections on the trailer. It sounds like there could be a short on the trailer side. I've attached a couple of articles to help troubleshoot. It could alternatively be a bad ground connection so you will want to check those on your trailer as well making sure they are bare metal to metal. Often trailer tail lights use the mounting hardware on the light as the ground connection, so make sure you have bare metal connections at those points. I've attached a couple articles to help. Let me know if you need to continue troubleshooting after taking these steps in order.

expert reply by: Jason S