What are these wires??

[Anthony.A]

There are 4 wires to the right of my brake resivour in the main harness, one blue yellow black and red wire, does anyone know what there for. Thanks

[ucf_stang]

From my understanding, they're auxiliary wires so you don't have to make a hole in the firewall to add things. if you look under your dash, you should see the other ends of those wires.

[Karls03]

Technically, they are called upfitters. For the 05 and up you can get a switch panel for them from Ford that mounts to the lower dash. I think 2 are 10 amp relays and 2 are 30 amp relays.

To utilize for say lights, run ground to batt or frame, run power to proper upfitter, connect upfitter switch, and you now have lights with a relay.

[trophy_23]

Originally Posted by Karls03

Technically, they are called upfitters. For the 05 and up you can get a switch panel for them from Ford that mounts to the lower dash. I think 2 are 10 amp relays and 2 are 30 amp relays.

To utilize for say lights, run ground to batt or frame, run power to proper upfitter, connect upfitter switch, and you now have lights with a relay.

I think he's talking about the ones under the hood that just 'dead end' on both side of the firewall. They are there to make it easier to bring wires into the cab (for connecting to upfitters etc)

[Anthony.A]

Oh ok yea I know were the upfitter connections are under the dash but I wasn't sure what these were