If you have the tow package you should of had a bag in the glove compartment with a aftermarket harness and the fuse and relay. If you have the 7 way connector the truck is all wired. all the fuse and relay locations are in the owners manual. The brake controller plug is behind the knock out for the brake controller and is the only one it will plug into. I have not installed a factory controller but have done dozens of aftermarket controllers. Since I work in a RV dealership. Ford is the only company out there that knows how to build a truck to tow a trailer and wire it right.
I have both the 3-way and 7-way plugs on the rear. Does that mean I will not need the harness and relay, that it is already installed? Or, will I need the harness and relay as well as the factory controller.
All of the trailer wires are fused separately you will have a trailer marker fuse for tail lights and marker lights which was factory installed as were the right and left turn stop fuses. There is a trailer charge fuse as well as a trailer charge relay that requires ign on for the charge circuit most of the ones I have installed had the relay installed but the fuse was taped to the aftermarket harness. As was the Trailer brake fuse they both must be installed if your pulling a trailer with electric brakes. There is a knock out on the dash where the brake controller goes the plug for the brake controller will be attached to it. Here is the part I don't know and that is if you install the factory controller will it read on your display once you put it in or do you need to go have the dealer turn the display mode on? We don't install factory controllers so we use the aftermarket harness and mount a controller where the customer wants it or in some cases we install units which can be removed when not in use. My guess is once you plug in the factory controller it will send data to the display with no other requirements. Even if it does not send data however it will work once you plug it in you just won't see the display on your dash.
fuse 37 in the passenger fuse box is brake controller power fuse 10 amps
fuse 17 is the brake controller output power fuse 30 amps in the under hood power distribution box.
relays 37 38 and 39 are for trailer lights in the same box
fuse 43 is back up light power for trailer
fuse 67 and 73 are fuses for stop turn and tail 67 is the tail lights which is marker trailer park lamps.
Fuse 21 is the trailer charge fuse 30 amps
relay 9 is the battery charge relay
if all of those are installed all you need is to plug a controller into the harness behind the knockout and you have trailer brakes.
Aftermarket ones I believe will work correctly once you wire them up (correctly) and will not need you to have the dealer re-flash anything. However, they will not take advantage of the on-board trailer control features Ford programmed into your truck.
That will require the OEM brake control module, roughly $150 I've found on eBay. It should be a snap to install yourself as the wire harness is already there if you have the factory tow package (4 + 9 pin trailer connections) and 2" Reese-type tow hitch. This will not work until you go to the dealer for a re-flash and every service manager charges differently. For 1 minute of their time to re-flash you would hope it would be reasonably cheap.
Question: I have. 2005 Lariat 4x4 with the tow package. Both the 7 pin and 4 pin connectors are there. Both power trailer lights as is. I bought the truck used and it came with a connector and relay for the brake controller. I installed the relay in the fuse box behind the front passenger kick panel per the instructions.
Now, is there any advantage, for my truck, to get a factory controller vs aftermarket? I don't see any knock out on my 2005 where a factory controller would go, so I assume it would have been a dealer installed option?
To my knowledge the factory brake controller was not a option for the 05. The only advantage I know of for the factory controller is on the new trucks with sway control other than that most after market controllers will preform just as well and some even better. Also many of the new controllers are designed so you can plug them in and use them and remove them when not in use. I have done a couple custom installs where we installed after market controllers in the dash by cutting a hole in the dash to insert it but few are willing to pay the extra to do that.
@1mainiac;Very happy to see you feel that way about Ford trucks and TTs, we just picked up our first TT ( 2012 Winnebago Minnie ) and will tow it w/ our 2012 XLT. We're in Western PA and plan to be on the road most of the spring & summer , where are you ? I'd like to maybe stop in sometime & pick up your lunch tab .
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