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OK, I know this has been beat up but dang, I'm still confused. 2016 F350. I cant understand this pass through wiring for a couple 7" LED lights. I think I only need to run a hot wire from the lights (and a ground, connected somewhere in the engine bay) going to the pass through wire by the relay panel in the engine bay (for my year truck, I think its the yellow wire for switch #1). That's where my understanding ends. Once I connect that wire for the switch I want to use, attach the ground, am I done or do I need to then run a wire from inside the cab at the drivers side blunt cut wire to the up fitter switch? I'm reading that each switch is fused and realayed, so my confusion is if I gota run a wire to each switch as needed.
Ok, so the 4(?) pass through wires are just that, just pass through wires, that still need to be connected to the actual switch. So I could just run one wire through the firewall directly to the switch, but then I wouldn't have fuse protection or relay I think. Hmm, but the switches light up from the factory, so power must be going to them, unless its just for the light on each switch.
So the switches ARE connected to the blunt cut wires to the left of the steering column but aren't connected to the pass through wires into the engine bay. Im just confusing myself I think.
So the switches ARE connected to the blunt cut wires to the left of the steering column but aren't connected to the pass through wires into the engine bay. Im just confusing myself I think.
Personally. I would use the upfitter switch wire or upfitter wire attached to a feed through wire to power a relay to control the lights. I would use one of the 30 amp relays to control the lights via a fused wire from the battery or another hot all the time 12 vdc source.
To answer your question simply, the upfitter wires are already through the firewall and under hood on drivers side. Powered And Ready to be used for anything exterior.
the passthrough wires are on pass. Side, and are used if you need to bring switched power back INTO the cab for any reason.
You will still need to run a wire from your drivers side upfitter wires to pass. Side passthru wires to get power back IN the cab.
Hope this helps a little.
OK here’s what I found on my 2016, the pass-through wires, all four of them do not matter. When I say that I mean that they aren’t the same colored wires as the Upfitter switches are, and that’s what was driving me nuts trying to find the yellow pass-through wire for switch one. Second, you absolutely have to attach the pass-through wires to one of the four upfitter switch wires, they’re not directly connected through the firewall. So since I’m running one light bar I chose the white pass-through wire, connected it to the yellow number one position Upfitter switch wire in the cab and now I have power going through the firewall. While I was in there I connected all for pass through wires to all for Upfitter switch wires.
I think they don’t connect the switch wires to the pass through wires is in case you want something wired up inside or at the rear of the truck.
I thought I saw a post somewhere saying that the newer trucks are wired completely from the switch to the pass thoughs, but my mind might be playing tricks on me.....,
I have power to my upfitter switches. They have a light on them and when I turn them on they light up. So I have power to the switch and all you should have to do is hook up the wire under the dash to the hot wire and find a ground.
Not ssure your engineering field is but I would still use a relay controlled by one of the upfitter switches to activate the lamps vis a separate fused circuit for the lights.
Larry, the switches are prewired to relays and fuses. I would think that should be sufficient for some LED lights. Maybe if you were powering a plow or 15k winch that you'd want a relay inline so ya wouldn't have to run 4 gauge wire all the way? Amperage draw for LEDs is minimal, my opinion. Oh, HH-60 Flight Engineer (retired)
As you know with aircraft, most pilots and FE's like redundancy. Was just a thought on using a low amp switch so the high amp switches are available for other items. Anyway.....good luck and happy lighting.
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