How to Find the Correct Stop Light Switch Wire on a 2017 Ford Transit T-250

Question:

2017 Ford Transit T-250. I need to connect the red wire of Tekonsha OEM Replacement Harness, 7 pin with brake controller to the cold side switch wire of the brake switch. Heres what Im finding with multimeter and test light: pin # _____ color ____________brake off ______brake on 4______purple / white________0.0 / dark_____12.13 / dark 3______black / white_________0.0 / light______0.0 / light 2______green / brown________0.0 / light_____11.89 / dark 1______yellow / red________12.13 / dark____ 12.13 / dark Pins 1 and 3 are out, as they dont change state at all. Pins 2 and 4 both switch voltage on when brake is applied. Pin 2 disconnects from ground when brake is applied. Pin 4 is never grounded. Which pin is the cold side switch wire to which I need to splice the Tekonsha controller wire?

asked by: Jon

Expert Reply:

The stop light switch wire that you will need to connect the red wire to on your brake controller is a purple/white wire located in the # 4 pin. You can see the process shown in the attached video on a 2016 Ford Transit T-250 which will be the same as your 2017 Ford Transit T-250.

expert reply by: Conner L