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Discussion Starter #1
Ok i know it is here somewhere but after searching for over an hour i have no hair left. Obviously i need to save the oil/water sensors a/c clutch wiring in my original harness but is the wiring for solenoid already in harness and tach wiring. Obviously i called cummins conversions and all they wanted to do is charge me $400 which is bs. (i have already donated enough). If someone could help me it would be appreciated. In the past they sent me a general wiring over view but they weren't making enough money. Also curious if most people are using mechanical pump or regulating 6.0 pump. Thanks
 

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what transmission are you intending to use behind the 12 valve?
 

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I've done around 80 engine harnesses for Cummins swaps. I can tell you I'd be pretty ashamed of the first dozen or so I did. There's way more to a decent quality standard harness than people think.

First, never believe what you read online without verifying it. people will make keyboard claims and recommend stuff that just doesn't work.

Buy the factory Ford wiring manual(s) for your exact truck. The thick ones with all the nitty gritty details inside. Then learn how to use the manual. How to understand it. There's a ton of information in there.

What I do next is figure out any unknown variables while the vehicle is running, like reverse engineer the cruise control and AC systems. Making sure I understand exactly how the system works. I once spent 3 days and over $500 in fuel to reverse engineer a cruise control system on a vehicle before taking it apart for a Cummins swap. That's the kind of stuff that makes the difference.

Once you know how the systems work you can decide how you're going to make/convert signals so things are happy.

Then I make a kind of point to point written on paper list of wiring modifications and connections that must be made for the harness to work. I put full descriptions of what each mod does because inevitably, I will forget and wonder what that was for down the road.

Then I strip the harness leaving all grounds intact. I utilize existing fused systems that make sense to power various circuits. That minimizes confusion down the road. I cut out anything that is corroded or splices that are just crimped and I do a mechanical splice with solder and adhesive lined heat shrink tubing.

I take the stripped harness and lay it in the engine bay on the new engine. My rule is under no circumstances do wires EVER run across the top of the engine. It's just ugly. There's a dozen sensor ports on every Cummins so this is not an issue. It's just laziness to run wires on the top.

Reroute everything so it lays nice in the new configuration. Use good plastic electrical tape sparingly to tape intersections and form the layout.

Remove the harness and tape tightly with wire harness tape. Yes, that is a thing and it's not cheap. I use Tesa tape. I like the 40MM wide smooth industrial stuff designed for class 8 trucks and heavy equipment that's difficult to cut with a fresh razor blade, but the fuzzy light duty stuff euro cars use works fine too.

If you use split loom punch yourself in the face. That stuff is a joke.

When you install the harness use vinyl coated and plastic clamps to route the wires. I like to reuse many of the OEM wire routing clamps from the vehicle and the Cummins engine. Don't allow anything to rub on anything else. Sometimes this is really hard.

If you don't understand how your harness is going to work, don't make the harness. Pay someone who knows what they're doing to do it. And seriously, $600 or more for a pro to do it is chump change for what you get (if it's a pro job). I charge $100/hr plus materials and most modern vehicle harnesses will be $1000+ at that for just labor and basic materials.

Tips- If you're using a P-pump engine buy a 100% new shutdown wiring harness. Buy new connectors/pigtails for anything that's ratty or missing. It's common to need a connector for the Dodge Sanden AC compressor. On a 6.0 truck you will need a gas cruise servo and you can buy the connector for that at a fair price from Ford.
 

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The 12v part of the swap is the easiest part, it's making the auto trans work. A friend put a 12v in a 2008 F450 with a auto trans and he had a fortune in making it work. Makes me so glad I went simple and used a zf5-42 diesel trans.
 

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The 12v part of the swap is the easiest part, it's making the auto trans work. A friend put a 12v in a 2008 F450 with a auto trans and he had a fortune in making it work. Makes me so glad I went simple and used a zf5-42 diesel trans.
Exactly. We all know how to make a 12 valve run. Problem is dumbing down the rest of the vehicle wiring so it's OK with such a simple engine.
 

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Discussion Starter #7
I drive a 4bt f150 daily that i always get compliments for. Being highly anal about building harness is great but not practical. I have 5 7.3 rigs so not new to diesels. People have good results from dcs tuning of 5r110 through an sct tuner. I hoped for a little help not pompus bs. I hoped for down to earth people.
 

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I drive a 4bt f150 daily that i always get compliments for. Being highly anal about building harness is great but not practical. I have 5 7.3 rigs so not new to diesels. People have good results from dcs tuning of 5r110 through an sct tuner. I hoped for a little help not pompus bs. I hoped for down to earth people.
Pompus BS????

How would you do it then? String wires from here to there and call it good? That's what 80% do and it works about 80%, but you asked for experienced advice.

How f*cking hard is it to take a little extra time and not half ass your wiring harness? Do whatever you want, it's your truck. I know what it takes to get 100% functionality from a wiring harness and really not because I wanted to, but because I figured out the hard way I HAD to if I wanted to do the mechanical side of the things that I really enjoy.
 

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You really just called a genuine, well written response to your question Pompus BS? Snuggletough, 9297oldram and many others on this forum have done multiple conversion, myself included. To come on here asking for help and advice then throw insults is just kicking yourself in the nuts. There are plenty of good folks on here who enjoy a good home built truck and will offer all the support they can but how about some gratitude for those taking the time respond.
 

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I drive a 4bt f150 daily that i always get compliments for. Being highly anal about building harness is great but not practical. I have 5 7.3 rigs so not new to diesels. People have good results from dcs tuning of 5r110 through an sct tuner. I hoped for a little help not pompus bs. I hoped for down to earth people.

So what exactly kind of help was you wanting from us?
 
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