2008 F 150 Brake Controller Question

Just an update. I called the Ford dealer parts department and they told me if I did not have the bag of fuses and relays that came with the truck that they could not order one and I would have to search online or the salvage yard. I know that is not true but they just did not know how to look up the part. I decided to call my local RV dealer and they sell them for $5. I will be heading there today to pick one up.

lasttruck wrote:
My 2007 came with a relay to add to the fuse box along with a pigtail to plug into the harness behind the dash for the controller to wire to.

IIRC the relay was for the 12vdc supply to the trailer.

There should be a spot for the relay marked on the fuse panel cover.

x2

Well I searched everywhere and I did not find a wiring harness. All of the fuses are installed in the distribution box and I am missing Relay #5. Trailer to battery charge. Is this available as an aftermarket part or do I need to go to the Ford Dealer?

Both my F-150s as well as the 2011 models I test drove all have two relays in a bag in the glove box. One for 12V trailer battery charging and the other for trailer brakes. The previous owner may have installed them already, but not likely if no brake controller. Check the owners manual for which fuses in the distribution box and then check your actual distribution box underhood.

lasttruck wrote:
My 2007 came with a relay to add to the fuse box along with a pigtail to plug into the harness behind the dash for the controller to wire to.

IIRC the relay was for the 12vdc supply to the trailer.

There should be a spot for the relay marked on the fuse panel cover.

You are correct - the relay is to disconnect the trailer from the truck when the engine is off. Saves running the truck batteries down when using the trailer.
OP needs a separate fused 12V supply for the brake controller.
Not familiar with 2008 F150 wiring, but a 20A in-line fuse holder connected to a live stud on the underhood fuse box is a sure-fire way to go if a closer connection is not available.

My 2007 came with a relay to add to the fuse box along with a pigtail to plug into the harness behind the dash for the controller to wire to.

IIRC the relay was for the 12vdc supply to the trailer.

There should be a spot for the relay marked on the fuse panel cover.