Troubleshooting Tail Lights on 2008 Mercury Sable Not Working With Curt T-Connector Installed
Question:
Vehicle: 2008 Mercury Sable I installed the custom wiring harness on my Sable this evening and thought it was super easy. I verified that the harness with the yellow wire is on the driver side. And I pushed in all the connectors until they were tight and they clicked. When everything is connected, the rear taillights and turn signal lights do not work. When I hooked up the trailer, the lights on the *trailer* work fine. When I unhook the harnesses and reconnect the Sables wiring like before, then the cars rear lights work fine again. The lights on the rear of the car should always work, since I hate to rely solely on the trailer lights. And it would be extremely inconvenient to disconnect the custom harnesses and revert back to the standard wiring setup every time I disconnect the trailer. If it was just one side, then I would suspect a broken wire on that side. But for both sides to stop working, it seems like a design flaw. Or maybe Im doing something wrong, but this is such a simple plug-and-play installation it would be difficult to mess up. Help? I must have this trailer working by Sunday! Thanks, James Frese
asked by: J F
Expert Reply:
The Curt T-Connector # C56015 is designed to be an easy installation on your 2008 Mercury Sable so since you made sure that the tees with the yellow wire was on the driver's side the only other things that could have been messed up is if you either didn't connect your Sable tail light wiring into the tee or if you didn't get a sufficient ground for this harness.
It's also possible that this wiring harness is malfunctioning. You can determine if this is the case by testing the wiring that runs to the plug that connects to your tail lights. If you are getting power on the end that connects to your vehicle but none on the wire that goes to the plug for your tail lights then you probably received a bad unit and it needs to be replaced. If this is the case then I recommend going with the T-One # 118447 instead because we have found over the years that Tekonsha tends to be more reliable than other manufacturer's wiring harnesses.
If power is getting through to the plugs on your vehicle side then I'm honestly not sure what is going on unless your trailer is pulling all of the power and your tail lights are just really dim. You can try disconnecting various lights on your trailer to see if it makes the tail lights on your Sable any brighter.
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