Troubleshooting Tekonsha T-One 118650 Driver Side Turn Signal Does Not Work

Updated 12/09/2024 | Published 12/02/2024

Products Featured in This Question

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

(73)

$81.71

Hook Probe Circuit Tester

(61)

$13.33

Question:

We just installed the 118650 T-one wiring harness on our 2011 Sprinter van. Order 121792895. We are wondering if the harness is defective. The passenger, running lights, turn signal, brake lights, and emergency blinker works great. The driver side running lights work. However the driver side turn signal, emergency hazard light, and the brake light do not work. To note, we are getting the rapid flashing turn signal on our dash like it would if the bulb is burnt out. Any advice in determining if the wiring harness is defective will be greatly appreciated. Thanks

asked by: Mike

Expert Reply:

Hello Mike, thanks for reaching out, and for your recent order. It is pretty rare for a converter module to be defective out of the box, but it is not entirely unheard of. What you can do to test this is use a wire tester like part # PTW2993 to test the input and output wires at the converter module. If the unput for the driver side turn signal is normal, but there is no output, the converter is defective. If you are not getting input on the wire for the driver side turn signal, that would indicate an issue on the vehicle side. Make sure the T-harness is fully inserted on the driver side and double check your ground. Check this and let us know your findings. If the converter truly is defective just give customer service a call and they can assist with the exchange.

expert reply by: Jesse M

Mike

12/2/2024

Hi Jesse, Thanks so much for your suggestions! I will test it today and let you know my results. Mike

Jesse M.

12/2/2024

@Mike Sounds good. You know where to find me.

Mike

12/2/2024

@JesseM Hi Jesse, Tested all the wiring today on the new wiring harness and all connections are good (used the conductivity setting on our volt meter). However, I think I may have found the culprit. I think the poor connection(s) was/were due to corrosion/oxidation on the van's existing wiring/plugs. Going to clean that off and try again tomorrow. Will let you know the results. Thanks again, Mike