How to use Upfitter Switches on Ford F-250, F-350 or F-450

You may be interested to know that your Ford Super Duty may be equipped with an enhanced upfitter switch board to help power your upfit component needs.

Ford F-250, fourth generation – (photo by Ford)

Six circuits

For your convenience, built in upfitter switches have been moved to the overhead console for easy access. Plus, Ford increased the number of switches from four to six. So now, you have more capability to control components, such as winches, electric spreaders, lights and more.

4 x 25 amps, 2 x 40 amps

To help power your upfit needs, Ford has increased the circuit capacity over the previous generation. There are now four 25 amp circuits. Plus two 40 amp circuits which can be configured to be hot at all times. So you don’t need to have the vehicle running for power.

Ford F-450 Upfitter Switches – (photo by Ford)

Enabling key-off battery use for 40 amp relays

In order to convert the 40 amp relays to key off battery use, there are a few steps you’ll need to take.

  1. First, you’ll need to locate the relay box under the engine hood, next to the driver side fender.
  2. Then remove the relay cover by pressing the tab and lifting it off.
  3. Next, locate the five amp fuse. You’ll then need to pull it out, slide the spacer over, and place it so the left prong is in the far left slot and the right prong is in the middle slot.
  4. Replace the cover and your 40 amp circuits are now set to run on battery power even with the key out of the truck.
  5. Keep in mind, to help remind you when power is flowing through the switch, it will remain illuminated to let you know it’s on.
Author: Nabeel K


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Scott Lipford
Scott Lipford
1 year ago

Can I use the upfitter switches to run rock lights under the fenderwells? 2021 tremor

1 year ago
Reply to  Scott Lipford

Yes. The 25 amp fuse would be more than enough to run plenty of LEDs to light up the underside. That would only work while the truck was running if you use the 25 amp though.