I've got the build sheet for my truck that I requested from Chrysler and it doesn't say anything about a tow package of any kind. My truck didn't have a hitch on it when I bought it or a 4 wire or 7 wire plug on the back. However, it has a blue harness under the dash above the wire harness that goes through the firewall to the engine bay. Is that the harness for trailer brakes? It has 4 pins.

 

I think that connector is for ABS or SRS diag.

Will

 

The electric brake controller connector is blue and looks like the picture below.



MODULE-BRAKE PROVISION - BLUE 4 WAY


CAV
CIRCUIT
FUNCTION

A
A400 14TN/RD
FUSED B(+)

B
B40 14DG
TRAILER TOW BRAKE B(+)

C
L50 18WT/TN
BRAKE LAMP SWITCH OUTPUT

D
Z998 18BK
GROUND

 

Is this it?

 

yup, looks like it. it has the wires required all connected, kinda nice. there are then 3 wires either run to the back of the truck (probably not in your case) or they are run to behind the drivers side front fender liner, they end at the harness that connects the rest of the rear wires. the 3 wires there are: 12v always on (on it's own 40A fuse) 12v switched for running lights (tapped off the previous 40A fuse with it's own relay so that you're not drawing current through the headlight switch and melting it) and the brake circuit output. The rest of the wires can be gotten off the back, which is just turn and brake, you can if you want put relays in for those circuits too if you have lots of lights (and then draw current through the 12v+). I had my wires end at the fender, cut them out of the harness, ran 4 wires (the three mentioned and a ground) in a new convolute right alongside the factory piece (it's a little fun to get in there, but not too bad) and put a 7 pin at the back.