I'm hooking up a brake controller on my 1997 F-350, and I'm having trouble figuring out the wiring under the hood. I have the square grey connector at the rear of the truck (blue, orange, and blk/grn wires) but when I traced it to the front, it's not connected to anything under the hood. It has another square grey connector with a cap on it next to the fuse box under the hood. Coming out of the fuse box is another square grey connector, but they are both male and will not connect. Is there a piece that goes between them? I've been looking over the wiring diagrams, but can't find anything that calls this out.

I bought the truck used about 5 years ago and the previous owner used it to plow snow and had a salt spreader in the back and safety lights on top. He cut off the 4 pronged flat trailer connector before he sold it, but I replaced that a few years back. He has wires going all over the place, so not sure if he's modified this somehow or what? The brake controller connection under the dash works fine and lights up when I step on the breaks, so I'm kinda lost at what I'm missing.

thanks

 

i had a wiring problem with my 88 like this almost, spaghetti wiring everywhere. I started from scratch an ran my own, and pulled the old out

 

Yeh, thinking of doing that, but he already has the fuse and everything in, so would like to use this if I can.

 

What I gather from others here with '92+ trucks is that the only connection you need to make is between the actual brake controller that you are installing in the cab and the chassis wiring, and there is a connector for that stuffed up under the dash on the drivers side somewhere. Add a fuse and the appropriate connector at the rear of the truck(if not already equipped) and you're done.

 

I've already got the brake controller installed, but I'm trying to find out what I'm missing in the front of the truck where the two cables are supposed to be connected but there are two male 4-pin connectors. One goes to the rear of the truck, the other goes to the fuse panel under the hood.

 

I just looked at my 92 and I dont see the 4 pin connectors you are talking about. Pics might help, but when I installed my brake controller the circuit to the rear of the truck was already complete. Do both of the connecters have a blue wire?

 

My 88 doesnt have 4 pin connectors, an blue wire from orig controller

 

The rear connector has an orange, white and blk/gn wire going to it. The wiring diagrams show the connector, but not how it's connected to the power distribution panel under the hood.

Here is a pic of the two connectors. The grey one is from the rear of the truck the black one is from the power distribution panel under the hood.



The OEM connector for the brake controller under the dash has the blue wire, but I can't follow it up under the dash and I'm assuming since it came with the truck it goes into the power distribution panel under the hood.

I did find a picture showing two connections going to the power distribution panel, so I'm going to look for those now.

'

 

I dont have the power dist, but i have the connectors in ur pic

 

My connectors are in the back tie wrapped to rear cross member

 

The two connectors go to the trailer relay box that hangs on the main fuse relay box.
Also if your brake controller does not work when it is plug in to the plug under the dash it is because the blue wire stops at the safety wall plug.

This is normal for a truck without the towing package. They used the same wiring harness in the cab for trucks with and without the towing package.

Trailer relay box:






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my brake controller appears to work because when I press on the brake it lights up. I just can't figure out how the wiring goes under the hood. I don't see a trailer relay box near the main fuse relay box, so not sure what is going on.

 

If you installed a brake controller with a plug to match the plug under the dash the brake controller will light up when you put on the brakes. But as I said above the blue wire from the plug under the dash will stop at the safety wall so the trailer brakes will not work.
As you can see in the photo below pin #2 is missing on the engine side of the safety wall.

You will have to put a pin in pin #2 and then run that wire to the plug on the rear of the truck.
Or cut the blue wire at pin #2 C205 cab side and then run it to the rear.

C205 Images below:


Complete wiring:


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Subford, thanks. I'll work on that tonight and let you know.

 

Ok, by tonight I meant the next time I got a chance. Everything was wired up today and yesterday and appears to be working fine. I haven't had a chance to actually pull the camper yet (I did connect it and check the signals and lights though) cause I got done too late and had to run into town before the stores closed. But thanks for everyone's help, subford, the pics were very helpful.

Now...time to change the fluid in the transmission and differentials before I pull this thing 300 miles in April!