Installing a trailer brake control on 2013 3500 express and I can not find a brake signal wire to tap into for the brake controller. If anyone can help , I could really use it. Thanks

 

Isn't there a brake light switch located just above the pedal up the shaft?

 

Yes it's there, I tied into the yellow wire on that switchb but only getting 1.7v. I think I need to get up to 12v.

 

Find the wire at the tail lights that turns on the brake light. Shouldn't be that hard. See which bulb lights up when brake pedal is pushed and check the wires to that bulb with a meter to see which one it is.

 

To install a brake controller there are (for Prodigy II) 4 wires to hook up to the van's electrical system plus the wiring going to the trailer brakes - brake power, ground, brake signal and trailer brakes. All sources are straight forward except for the brake signal. Normally you pick up the brake signal from the brake switch at the brake stop light switch. On the 2010 Express there are four wires coming off of the stop light switch. The stop light signal is normally 12v and goes to 0v when the pedal is pushed. This will not work for the brake controller. A second pair of wires provides a brake signal to the transmission and is normally 0v and goes to 12v when the pedal is pushed. This is the wire you need to connect to. On the 2010 express van this is a light blue wire with a white stripe in the "D" position on the 4-way plug. You can back probe the connector with a test light to verify the wire that goes from 0v to 12v when the brake pedal is pushed with the ignition switch on.

 

I found the wire on the brake switch, but did not put out enough volts for the brake controller. I also pulled out the BCM, but started to get uncomfortable digging into it. So what I end up doing is what you guys helped me out with I tapped into the third brake light, the blue wire on it goes form 0 to 12v, just a little more work running wire down the van. I would just like to say thanks for all the input and you guys are great for helping out.
Thanks again!