I've got an '05 F450 Super Duty, V10, Manual Tran, 4x4 that is "inoperable". (The mining company I purchased it from mined some parts off of it and I have to figure out what is missing.) I'm working w/ a rebuilder/upfitter (to bring it back to life and install dump bed) who appears to be stumped. With the original wiring harness in place, the rebuilder got the motor to start but it dies right away (as if some sort of anti theft function notices some missing components/wiring issue and kills the truck). There is a wiring issue that is likely the problem - there were cut wires on the wiring harness under the dash near the fuse panel, and I've found a brand new (VIN match) wiring harness which is now installed. The new harness has 2 connectors on it (where the old harness had 8 cut wires) near the fuse panel under the steering wheel that don't have a place to land. They don't fit any of the ports on the fuse panel. It is believed at the moment that there is a missing module (or 2) that should be mounted nearby and are not. One connector is double row grey w/ orange insert, and one connector is single row black w/ red insert - both connectors have 4 wires each.

Thanks.

Scott

 

Scan for codes and post pics of the connectors. We probably can help a little more. The fact that it starts is a good indication. It could be a security issue but not sure short of getting any codes that are in the system.

 

As you can see in the pics, We're looking at the back side of the dash assembly - I'm heading out in a few minutes to reinstall the dash in the truck. One pic shows the length of the pigtail with the two connectors coming out of the harness and being roughly the same length as the pigtail that clips into the back of the fuse panel. The other pics show front and back of the connectors. So... no codes yet, and I'm not sure my rebuilder is going to give them to me - he's not a very good communicator. I've not heard it start, that's just what he's told me, but I'm trusting that he has at least given me accurate info. Hopefully these connector photos will get some sort of clue? My guy has been sitting on my truck not doing anything for the last 2 months, and I'd like to get as much as I can give him when I get the dash back in - which should be complete today

 

I got the dash back in and everything reconnected that I knew where it went. The back of the fuse box has 2 ports without connections (and pins in the ports, so there must be something that is supposed to connect). I was initially thinking that the cut wires on the main harness that got replaced were going to land there, but those two connectors on the new harness don't fit the fuse panel. Knowing that, I'm now seeing 10 cut wires in the 2nd wiring harness (pic 1) that were neatly tucked down on the side of that second harness and I've peeled them out to get the pic and count the cut ends. That 2nd harness goes through the firewall (pic 2) next to the pass through for the main harness, and land in a big connection under the hood (pic 3). They don't quite match wire for wire with the two new connectors on the main harness since there are 10 of them and only 8 in the new connectors on the main harness, but I'm now suspecting that it may not be modules that are missing, but 2 matching connectors (plus 2 stray wires?) There are also those 2 ports on the back of the fuse panel looking for connectors. From the looks of the cut wires on the 2nd harness (zip tied) it appears they could have been cut and the truck still functional since they are tucked out of the way - why would they do that if they were robbing parts off of a parts truck? The missing connectors on the back of the fuse panel have color coded ports. One is light purple (which looks like an aux harness connector fits into a different light purple port, so potentially that empty light purple port is for those cut orange aux harness wires that can be seen in the fuse box pic (pic 5). The other color coded port is blue - which 3 of the blue ports are occupied by connectors from the main wiring harness and one is occupied from a connector from that 2nd wiring harness (with the 10 cut wires). The 5th pic is an aux fuse box at the tail end of the aux wiring harness. It will reach to the glove box area. Any idea where it mounts?

 

I believe those wires that are blunt cut, are for the upfitter switch, if you choose to install one.

 

Thanks Ligito. I believe you are talking to the orange wires in the pic above the fuse panel. I do think they are for some sort of upfitter switch since they are in the "aux" harness.

 

The rebuilder said there was no communication to the ECM so there were no codes. Not sure why there would not be communication to the ECM. Not even sure where it is - I totally disassembled the dash and had expected to find it under there and it was not (its under the dash in my old toyota). I think I've seen something that suggests it lives somewhere near where under the hood (near pic 3 above?). Potentially those cut wires in that second harness provide that missing communication link to ECM? That main harness that I purchased was discontinued by Ford but one dealer in the country had it in back stock so I purchased it. They can't even give me a part number for that secondary harness that I've now identified has 10 cut wires, and of course there appears to be nothing in existence resembling what I would call a wiring diagram that shows the color codes of the wires and what points they run between.

 

Is the ECM behind the under dash fuse panel?

 

I've had the entire dash apart. The ECM is not in the dash. It does seem likely at this point that it is supposed to be under the dash and that the two connectors from the main harness and the 10 cut wires from the secondary harness must somehow connect to the ECM. (and at least one of the 2 remaining unfilled ports on the back of the fuse panel - the other seeming likely to be for upfitter aux wires). I've seen pics of the ECM that is supposed to go on this truck and it has 3 wiring ports on it. Does anyone have access to a wiring diagrams of the wires that go to those ports? Or to the the connectors on the back of the fuse panel? (what color goes in which hole of the connector).

Thanks.

Scott


...

 

Ligito,

Its starting to come together - You're last comment asking if the ECU is behind the fuse panel. I was looking for a stand alone unit like my toyota had. My rebuilder has now communicated with me, and he now has the truck running -- not running well yet, but running. He says the ECU is part of the fuse panel and it is in tact and now communicating w/ the OBD port. He says the main harness that I have now replaced was the primary issue. Its odd to me that the old harness and the new harness were exact matches except that the old harness had 8 cut wires, and the new harness had those 8 wires leading into 2 connectors which are now laying loose under the dash and not connected to anything - so in my opinion they may as well still be cut. I'm thinking the problem was because he did not have everything connected before and the old harness was actually fine. I do know that the wiring connectors to the steering wheel he had not connected and I connected them - I'm suspecting that the issue may have been an anti-theft shut down issue because those wires were not connected? Does anyone know what the 2 connectors which are in the 1st 6 pics above go to?

 

I am not sure what they go to but you apparently don't have their mates anywhere you can see so I would guess they are for a different application. If everything works I wouldn't worry about them. Ford didn't make a harness specific to a build sheet so those harnesses were used in many different configurations. It sounds like you are on the right track now and hopefully you will have a good running truck soon...