Yes, I know the topic of upfitter switches has been talked about a lot...but.

In order to power anything INSIDE the cab using an upfitter switch....you've got to pass a wire from the engine compartment back thru the FIREWALL into the cab.

SO...my question is....does Ford have pre drilled "knockouts" or rubber grommets in the firewall that easily allow me to "punch a wire" thru the firewall?

Predrilled holes / rubber grommets make so much sense, I hope Ford is smart enough to do this especially since they tout their upfitter switches so much!

Every vehicle I've ever owned would require me to "stand on my head" under the hood with a drill trying to drill a hole thru the firewall and hoping I don't hit something that I shouldn't....and that the hole can be sealed from drafts to the cab area.

 

Im also interested in this as i'm planning to run a 4 AWG wire into the cab from the engine bay

 

There will be pass through wires from under hood by master cylinder to behind the ebrake under the dash. Ussually 4 of them. There are also a pile of upfitter wires capped off and labeled under center console on firewall to the upfitter side and there is also plenty of holes and caps you can go through, just be careful not to tear any other wires. The manual talked about the upfitter wires. I would have to look to verify the pass through wires, but easier to check under hood at master cylinder, tied to a big wire bundle, they are ussually 10 gauge, red, black, white, yellow with black end caps. I will try and find.

 

Here's how I did it:

https://www.ford-trucks.com/forums/1...-interior.html

 

The pass through wires are on the right hand side secured to the harness, and inside the cab behind the cick panel, hard to get to ford could have made them longer.

 

If you're saying the passenger kick-panel, those are not the output from the upfitter relays. Those are for something like the upfitter IMU. The owner's manual is even wrong. We wen through this here about 1-2 months ago. The stubs are in the engine compartment only.

 

What wb6 is trying to say is why not use the pass thru wires on the passenger side instead of compromising the firewall or hitting something you shouldn't. Simply run a wire from the upfitter bundle on the driver's side over and across to the passenger side and connect to one of the pass thru wires (there are 4) then pick up the pass thru wire inside the cab at the passenger kick panel. See page 2 of this document:

https://www.fleet.ford.com/truckbbas/non-html/Q-256.pdf

 

AHHHH ....

Now I understand you. That makes great sense as long as you don't need to use those for their original purpose.

Good idea. I wish I had seen that bulletin. A lot safer and a lot easier to get to.

 

Taht s their purpose, they are just pass wires, dead ended and capped off on both sides. The PTO cabin wires are also there but lower and tucked behind the panel just in front of the RH door. But you need to keep in mind the amperage you want to run through them.

 

Yep, This^^ I just read this earlier today at https://www.fleet.ford.com/truckbbas/non-html/Q-256.pdf

I couldn't understand why Ford wouldn't have put pass through wires where you could run wires from the up-fitter relays to a pass through wire. I couldn't imagine having to punch or cut holes in rubber grommets that were meant for something else, just to install a dash camera or other low amp part.