Ford Transit Upfitter Auxiliary Switches

Ford Transit Upfitter Auxiliary Switches

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The Ford Transit can be ordered with the optional Upfitter Auxiliary Switches (Option Code 67C). Each switch is ignition supplied (they only works when the key is in “run” position) and can provide a 12V / 20A max output to an auxiliary load (such as an Air Lift Spring Kit Compressor, Exterior LED Bar, etc.).

Please note that the information below is valid for the 2015-2019 Transit. For 2020+ the harness has been moved to the glove box. We’ll update this page soon with the latest instructions!

So, you ordered the Upfitter Auxiliary Switches option and are ready to connect a load to it? NOT THAT FAST! You still have to order an additional accessory from the Ford dealer: The Wiring Pigtail Kit (Part Number WPT-1408). Without it, you don’t have access to the output of the switches:

Ford Motorcraft Wiring Pigtail Kit WPT-1408 for Upfitter Switches
WPT-1408 (EU2Z-14S411-XA)

Now, let’s get the driver seat out of the way because this is where that we access the switches output. There are four screws to remove; two in the back of the seat:


and two screws in the front of the seat:


Don’t take the seat off yet! We still have to detach the electrical harness:


We’re now going to take the batteries cover off. We have the dual batteries option; your setup might be different!

Remove those two screws to free the metal plate:


Here is the C33-H connector! We will connect our WPT-1408 pigtail to it.

C33-H Connector

While we’re here, if you ever blow one of the Upfitter Auxiliary Switch 20A fuse, this is where to replace it (see Fuse Panel in the picture above).

BEMM C33-H and Fuse Panel Location

The WPT-1408 Wiring Pigtail kit comes with four crimp splices and shrink tubes, but we decided to install female quick-release terminal instead. This way, we can easily add or change the loads in the future:

WPT-1408 with female quick-release
WPT-1408 Wiring Pigtail Kit with female quick-release terminal

We can now connect the WPT-1408 Wiring Pigtail Kit into the C33-H connector:


Turn the ignition on and flip those switches up!

(you can use a multimeter to find out what switch power what wire…)

You might be interested in…

(We’re using the upfitter auxiliary switch #1 to power our Air Lift Spring Kit):

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About us



Hello! We’re Isabelle and Antoine 🙂 In 2017, we sold our house (and everything in it), quit our engineering careers, and moved into our self-built campervan. Every day is an opportunity for a new adventure... We’re chasing our dreams, and hopefully it inspires others to do the same!

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Thanks to all of you, we managed to negociate group discount on these. Strength in numbers!

6 thoughts on “Ford Transit Upfitter Auxiliary Switches”

  1. Bonjour Isabelle et Antoine.

    Just to share that I have a Transit 2022 AWD with the electric parking brake and found out that there is no such connector (C-33H) with that version. Not sure which option combo I took to end up with the electric parking brake though. I don’t mind as it is also opening options underneat but this mean that I will have to go the other route and access the other connectors behind the glove comparment. Just to share.

  2. Salut, J’ai trouvé un transit 2021 avec seulement une batterie sans l’option Upfitter… es ce que c’est possible de l’aménager pour installer l’alternateur? Par exemple ajouté une batterie? Merci

  3. Hi I have a 2019 transit. The upfitter switches look identical to the ones shown in the upfitter switch guard. I would like the purchase it but I wanted to know if you think the upfitter switch guard will fit a 2019, since the description says it for 2020+. Thank you.

    • Hi,
      The mating surface is slightly curved on previous Transit years (2015-2019) and the cover unfortunately doesn’t fit. I tried making a cover for 2015-2019 Transit but I couldn’t come up with a satisfactory finished product 🙁

  4. Hello Isabelle and Antoine!
    We have been inspired by your excellent van conversion site and adventures. We bought a 2021 Transit (WonderBus) and have been several camping excursions for over a year as work allows. Fantastic experiences! We are now getting some professional help with the simple “rolling tent concept” enhancement. We did order the Upfitter Switches and a wiring harness with the van. We are also curious about utilizing the switches for things like perhaps the MaxxAir fan or any smart moves for the 4 switches. Do you have any more insight into resources for the 2021 machine? Thank you!

  5. We have a 2021 arriving 9-15-21. Can’t find any infor about how to use the benefits of the dual battery, dual alternator, Upfitter Interface Modul, Upfitters Pkg that has modified vehicle wiring system, auxiliary Fuse Panel and how to use all of this to make it easier to add power to our van. Do you have suggestions, or know where we can get more infor. Thanks in advance., U


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