trailer wiring by color/function
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trailer wiring by color/function
I'm sure this has all been covered a thousand times, but I'm the new/clueless guy, so please be patient. I am replacing 7 blade plug on 03 F250. It was damaged and some wires torn out when I got the truck. I could sort out most wires by testing with voltmeter. However when it got to large orange and blue wires I got stumped. Blue has 12vdc always. Orange nothing. But wait...as always a catch. "trailer battery charge" fuse is blown. Is that the orange wire and that is really my 12volt power? If so blue should be brake controller and if it is in fact brake controller then should it have 12vdc all the time?
Joe
Joe
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From: Bristol, TN.
Okay, that's a curve ball. There is nothing at the seven pin that should be hot all the time. No way it can be brakes or the brakes would be continually engaged. Can't be charge lead or your truck battery would go dead feeding the trailer battery. That feed should switch with the ignition.
Can you tell us which functions you have been able to identify? I am wondering if someone was doing their own wiring prior to your ownership.
Steve
Can you tell us which functions you have been able to identify? I am wondering if someone was doing their own wiring prior to your ownership.
Steve
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In the interest of full disclosure there is a red(and clearly not factory) wire plugged onto a spare terminal in the fuse panel. It goes in the direction of, hard to tell for sure, a bundle of wires with a Ford label describing wire colors for trailer brake controller that is just inboard of steering column. Disconnecting or connecting the red wire had no effect on above issues. I am working under presumption that while this brake control 'harness' exists I don't have brake controller integral to truck. I certainly don't see an aftermarket one.
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Hotshot
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From: Bristol, TN.
So to establish your functions, you are using your frame as a ground? If you go test pin and orange will the orange function as a ground?
Steve
Steve
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I used frame as ground until I verified white wire had continuity to frame. I think, too many head scratching moments, that orange was NOT a ground, just no voltage present when I checked it. Couldn't check with applied brakes, being alone this evening. And I'm thinking even then not a sure thing depending of brake controller either not being there(my case), or type of controller.
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From: Bristol, TN.
Sorry, with no white on the list, I wasn't sure. As far as you know, are all the wires coming from the factory harness? I am still trying to get my head around why there is a constant hot. No batteries taps?
Steve
Steve
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Ooops. I left white off list initially, but yes it is there and is ground. As for factory wiring harness, I would have said yes until I found the blue with 12vdc on it. I was looking for orange to have the power and blue to be trailer brakes. So I still have some tracing to do. I was kinda committed to putting it all back together last night, even if it wasn't right. We are getting our leftovers from Bill right now here on the Kansas/Oklahoma border and didn't want to leave a bundle or wires dangling as I drive in this crap. If it ever stops raining I'll get under the truck and chase them to hopefully an origination point. I do appreciate all the help! As usual, when I get into something, I get "huh, never seen that before" from the folks who are way better at this than me. Just my luck.
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From: Huntington Indiana
When working alone and need brake on. Cut a stick or something to activate brake switch. Place stick or,whatever between brake pedal and seat to activate and keep on. Good luck on your tracing wiring. You will get it done . You have a lot of great help here
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Yes. A lot of help already.
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But wait there's more. Talking to a buddy and he had same always hot blue wire on dodge. It was brake control wire before controller was hooked up. I would love to hear someone make sense of that. But does clear up what I may be looking at. Means orange has to be aux/12v I think? And if I can get it working and brake controller installed I should be set. Which almost starts new discussion. Anyone played with brake controller harness under dash on 03 f250?
Lead Driver
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From: Huntington Indiana
If it is like my 04 there should be a pigtail connection in the center of the dash behind everything. Hard to get to. I had pigtail when new in glove box. Plugged right in and away we went.