Trailer Wiring Harness Installed on 2009 Nissan Versa Causing Brake Lights To Stay On

Published 09/24/2021

Question:

2009 Nissan Versa Base 1.6 ltr. This t-connection has worked fine for a long time. Recently, drivers following me, told me my brake lights are on all the time. I think only when my headlight switch is on and not towing. I connected a Curt 4 flat test light and all three lights come on, only dim. And thats with the car off and parked and no light switches on, statically. All 3 lights are bright when I turn the headlight switch on. I recently changed a burned out drivers side tail lamp. I made sure the white grounding wire is grounded to chassis. Its looks like a floating ground. I can not get the connectors apart to isolate the converter. I look at videos but they only pull them off with a pic. And none with the towing pig tail connections.

asked by: Tom P

Expert Reply:

If I had to guess, I'd say that there's most likely a short circuit in the converter box. You can confirm this by disconnecting the 12-volt connection at the positive battery terminal that leads to the converter box. If this fixes the problem, it confirms that the converter box has shorted out and needs to be replaced. You should be able disconnect the connectors by pushing on the release tabs then pulling the connection apart.

For a replacement, I'd recommend the Tekonsha # 118545 T-One wiring harness which would install as shown in the linked video.

expert reply by: Mike L