Troubleshooting 2010 F-150 and Tekonsha Primus IQ Cant Shift Into Gear Without Override Pressed

Question:

I have a 2010 f150 promise braking system was installed when I bought the truck Ive been driving it for 2 years tonight I cannot put my truck in gear unless I hit the button on the side of the box

asked by: Jason W

Expert Reply:

I do believe that this malfunction you're seeing with the Tekonsha Primus IQ # TK90160 has to do with where the controller is wired into the stop light switch on the rear of the brake pedal; if you hard wired this controller into the vehicle I would check the connection and make sure that everything is connected properly. Most vehicles with automatic transmission won't shift into gear unless the brake is pressed, so it would seem that it's somewhere on the connection from the controller to the stop light switch on the brake pedal. You'll want to disconnect everything and using a circuit tester like the # PTW2993 test the cold side of the brake light switch to see if it provides power when the brake pedal is pushed. If not, I'd check to make sure all of your fuses are in good working order if you don't see any damage.

If you can't locate the issue on that wiring where you've connected the controller to the brake light switch, let me know and I can give you a couple of other things to check out, but my first instinct tells me it's something in this realm.

expert reply by: Erik B