Hi everyone,

I'm a complete newb when it comes to automotive electricity so you'll have to be super blunt with me to help me out.

I bought UJOINT's ARB onboard air system just to air tires up and down (no lockers yet) for my 2010 V10 E350 and I'm almost done with the install.

• I have the supply loom for the ARB compressor wired directly to the posts on the auxiliary battery on the frame rail on passenger side and I have the compressor on the frame rail on the driver side. I know this battery has a good charge and I have a separate DC outlet wired to it as well which is working.

• The switch loom is mostly hooked up EXCEPT the only two wires I have not connected are the supply wires for the switch itself up at the dash.

I need to find a wire that is hot when the key is on or turned to ACC and I need to find a wire that is dimmable so that the ARB switch lights up with the dash. How do I do this??? I've tried turning the switch to turn on the compressor but it won't kick on yet. I assume the switch itself needs power to work? Or is the power only for the light?

I have a wiring diagram book, and I know where my fuse box is and what the different fuses do - 1-4 are empty and 42 is an upfitter switch. How do people fit "add a circuit" type products under the lid of the fuse panel? Is this what I should use? I know what the 4 wires going in to my dash dimming switch do - two are dimmable switch wires that aren't differentiated in the wiring diagram book...I suppose I could just choose one of them to connect for the dimmable wire?

Help, please!

My switches are dark until on so I don't worry dimming. Now for the keyed you can use the switched power for the radio.

__________________
Kelly, Claudine, Sophie dog, Bell the redheaded step child and Gooseberry RIP.

Most the time the Copilot is Now Sophie dog the noise maker.

2000 7.3 PS Quigley/RB30 with a 6 window poptop.

OK - I found it! Ended up finding a female grey junction box not plugged in to anything and it looks like it was identified in the wiring diagram I found on fleet.ford.com. My wiring diagram book is still confusing for me to use. Anyways, yellow/red was indicated hot for on/run and it was according to my multimeter. I hooked my dimming wire into the dimming switch itself but this doesn't seem to work. Regardless, I got the compressor running and tested it and everything is good to go!

I can't imagine having to have taken more of the dash apart to find power to the radio or dig into the harness which looks like it's running that direction. Anyways - learning curve is steep for me on this but I'm making progress!