Upfitter switch-Help please.

[ADieselguy]

I'm installing air horns in my 08' F250 Powerstroke and can't figure out how to connect to the upfitter switches. I had this system on my 00’ Powerstroke (without upfitter switches) and had no problem with the wiring but now I’m completely lost.

Let me explain exactly what I've done so far. The two solenoids (two horns) are wired together to be hooked up to #87 on the relay. Next I have the compressor and pressure switch wired together (which I want to connect to one of the upfitter switches for power). Number 85 is the ground and number 86 to the horn button. Number 30 on the relay is power to the battery. Can I wire the relay (#30) to one of the upfitter switches instead of the battery? I read somewhere on this forum that all the upfitter switches on the 08’ are already hot although when I check them I get not reading at all.

There are four wires coming thru the firewall that are supposed to be from the upfitter switches and there are 7 wires coming off the back of the upfitter switch, white/w Blue, white/w purple, black/w purple, grey/ w black, green/w blue and solid green, none of which correspond with the wires coming thru the firewall. Those are grey/w orange, white/w orange, brown with/w white & solid yellow.

Do I have to connect something to the fuse panel? I’ve got my entire dashboard apart including the glove box and can not find any fuse panel. Am I blind or just looking in the wrong place. I could just as easily hook this entire system up WITHOUT using the upfitter switches but then I’d have to add my own switches.

Any help would be greatly appreciated.

[GrampyJim]

The upfitter feeds are hot only when the key is on... many posts have referred to https://www.fleet.ford.com/truckBBAS/topics/f-sd.html

[ncitro]

As I recall the upfitters go to wires under the steering column. The wires you see sticking through the firewall deadend below the steering column as well, but they are not live. I would recommend you find the wire coming from the upfitter switch and splice it to one of the wires going through the firewall, which will then make one of the wires under the hood live for you when the upfitter is on. I cannot recall the color of the upfitter switches off the top of my head but if you do a search I am sure it will come up.

[ncitro]

Here you go I pulled this from Grampys link:

Aux 1 CAC05 Yellow 30 Amp
Aux 2 CAC06 Green/Brown 30 Amp
Aux 3 CAC07 Violet/Green 10 Amp
Aux 4 CAC08 Brown 15 Amp

[ADieselguy]

Thanks for everone's help. Can anyone tell me where the fuse panel is located on my 08'? I just bought this truck (used) and I am waiting for the owners manual to be delivered.

[reconr1]

driver side under hood, kinda hard to see, you have to remove a little thing(i have no idea what it is) and its under that.