Brake controller question

caribe makaira asked me to post a pic of the underdash plug, shown below. Larzzz, there are no wires under the rear of my truck to tap into. The only harness coming back is for lights. My son in law's f150 has exactly what you describe and it makes it easy. It looks like what TnShooter advised is the best solution. I don't know what advantage the under dash plugs give me, if it is the correct plug. Sorry for the lousy picture.

 

I have the factory tow package (05) with the 7 pin connector at the hitch and that's the same plug I have in the kick panel up front. So if that's the factory plug it's a mystery to me where it's going? into a flat 5 pin in the back? I'm sure others on here will help clear up next steps.

 

Maybe the wire going to the rear bumper (electric Brake) is missing.



The vehicle might have the wire going into the male connector but no terminal or wire in the female connector. (ID2)

 

OP follow the of your 5 pin, im betting it goes up to a lil box and its all aftermarket just like your hitch if you dont have the tow package.

 

The 5 pin just adds a reverse power output. Nothing to do with the Electrical Brake wire...

 

5th pin is simply an accessory wire, most often used for reverse (which it likely is in this case). OP could easily keep the aftermarket box thats being used for turn signals / tail / stop light mixing. chop the 5 wire plug off and wire in a round 7 pin and add in the trailer brake controller wiring.

Pops did this on his first gen taco that had a 4pin box, he ran a brake controller chopped off the 4 pin and mated a 7 pin to it with the brake controller wiring so he could tow a small tear drop that had electric brakes.

 

OP, another bad news; the wire from the engine fuse box where the towing brake module would get its needed power might not be there.

The wire from IA4 to the brake module connector (T7) is there, but from IA4 to the engine fuse is not...

 

This is getting a little head spinning. You guys understand this on a whole different level than I do. Thank you for all of your help and time. I took the tail light off and traced the wires to the harness. You are correct caribe, this is an after market harness solely for lights. The extra wire. blue is likely for back up lights or other options . There are no trailer brake wires to the bumper. So my impression is that I shouldn't bother to use the connecter under the dash because it is likely not complete missing the connection to the engine fuse box. I looked at the the spot in the fuse box for brake controller fuse and it is not complete. It appears to me that the solution posted by TnShooter makes the most sense?