Upfitter Wiring Harness Discussion

[_Slayer]

I received mine as well. Quality looks great and I'm excited to get the installation going. Likely won't happen for a few weeks. I have some other priorities in the short term.

 

[Mad_Max]

So what is the consensus on where to connect the ground wire? Has anyone who has done the install found a good body ground point that works or is the battery ground the point of choice?

 

[BroncOh]

So what is the consensus on where to connect the ground wire? Has anyone who has done the install found a good body ground point that works or is the battery ground the point of choice?

Use the bolt next to the battery on the fender.

 

[Tightlines]

Use the bolt next to the battery on the fender.

They moved it to the Drivers side on 23 & 24

 

[IndecisiveOne]

They moved it to the Drivers side on 23 & 24

I used this ground on passenger side next to the battery. 2023

 

[Tightlines]

View attachment 155851
I used this ground on passenger side next to the battery. 2023

I honestly didn't see that or even if I did, I wouldn't have been sure that was a ground. Thanks.

Now we just need some more interest for @Cblaxx19 to make some more.

 

[HelmPilot]

So where are you 23/24 model year guys fastening the ground cable? Does the next batch need a longer ground cable?

 

[HelmPilot]

I think I read somewhere that it’s better to run to a body ground rather than direct to negative on the battery for some technical reason. Wish I had bookmarked that discussion because I would think direct to battery would be best but I’m not an electrical engineer.

 

[devildog]

My 24 has a ground on the driver side by the battery/ coolant reservoir… the ground cable will need to be much longer in order to connect here.

 

[Maine Guide]

Doh

 

[Tightlines]

So where are you 23/24 model year guys fastening the ground cable? Does the next batch need a longer ground cable?

See 2 posts above the quoted post. Red truck picture.

 

[wearenh]

I think I read somewhere that it’s better to run to a body ground rather than direct to negative on the battery for some technical reason. Wish I had bookmarked that discussion because I would think direct to battery would be best but I’m not an electrical engineer.

Link to two agreeing opinions by electrical engineers

 

[HelmPilot]

Awesome thank you!

 

[HelmPilot]

If anybody out there got one of these and is having second thoughts or is not quite ready and can wait I’ll be glad to take it off your hands at full value plus something for packaging and shipping.

 

[Canyon Trekker]

I think I read somewhere that it’s better to run to a body ground rather than direct to negative on the battery for some technical reason. Wish I had bookmarked that discussion because I would think direct to battery would be best but I’m not an electrical engineer.

This actual question is on a very basic engineering level and doesn't need a lot of doubletalk and fluff to explain it. Reading through the posts that @wearenh posted from that site, (thank you for that link) if you add all of the responses together and pull out the double talk and BS parts, they have it mostly right.

Reasons to use the chassis as ground:

*The chassis is a substantial conductor in which you can tap into anywhere and run a short connection and avoid extra cables (reducing resistance) to make the ground connection. Drawing a lot of current through an inadequate wire over distance has a potential for burning up.

*Most accessories come with an adequate dual lead to run directly to the power source, both negative and positive. (Such as light kits from most major manufacturers.) The negative is usually a ring terminal so you can conveniently hook it up to the chassis anywhere. The connection could be shortened and hooked up close to the device as well, using the chassis as the return, eliminating the negative wire.

*The main battery is attached to the chassis through a heavy gauge wire and only limiting current capacity is the length and size of that wire. It is usually heavy enough to run most accessories in a vehicle. However, in some cases may be inadequate. Please read on.

*It's a bad idea to stack too many connections at a single point. (All hooked up to the negative terminal on the battery or even the chassis) This has a high potential for making poor contact over a period of time due to oxidation, can come loose easier, etc. This is why the positive wire goes to a distribution point and not all stacked together. (And yes, you can conceivably do this with a ground block for the negative lead as well.)

Reasons to use a direct connect to the battery:

*If you have a substantially high current draw on the battery and pull all current through the single wire going to the chassis, it may not be adequate for the load. A heavy gauge wire hooked directly to the battery can supply much more current than the relatively small wire connecting the battery to chassis simply because it has less resistance. (Such as inverters that use 2/0 or even 4/0 wire to make the connection.) I can't speak for winches; I don't know if they are direct connected to the chassis or run a negative cable. Obviously, follow the manufacturers hookup recommendations.

*The truck chassis has small wire connections from panel to panel to make the chassis "one ground" and conduct better than screws and rivets by themselves. These small wires are generally adequate for accessories, maybe not for heavy accessories like an inverter or winch.

*There is no danger in hooking up a cable to the battery direct so long as you are diligent and avoid the above scenarios.

*Upfitter extension ground wires (as designed by @Cblaxx19) can be hooked to either the chassis or the battery direct, the current involved in these connections are relatively low and will not create fire hazards since it is a single heavy gauge wire connecting the negative of all accessories through this single connection.

*The battery terminals already have screws that you can connect a device directly to. I would say the Ford engineers did that for convenience.

Conclusion, for the upfitter wire extension, hook the ground wire up to the most convenient spot, chassis or battery terminal. And if you hook it to the chassis, make sure there is no paint on the spot you are attaching it to. Or just hook it to the battery negative terminal screw. (Not the tightening screw.) You can also use the chassis at any point for the negative connection for your accessories, even if the harness is connected to the negative terminal direct.

footnote: In the photo, my charger maintainer negative lead is hooked to the tightening screw, it has very low current and is convenient (and safe) for my purpose. The other screw is a good point to connect for higher current draw. I left mine available for future accessories. Both negative battery terminals have these screws available.

 

[🇺🇸BoonesRide22🇺🇸]

Has anyone with a MY23+ installed theirs yet? Pics? Where are you grounding? Not sure the above (red truck) pic will work.
Going to get into mine next weekend. Just trying to get an idea.

 

[Pmichael]

2023 F250 Tremor. Here’s my first attempt with mocking it up to see how it will fit. Easily got to the upfitter wires. Attaching the wires to the harness will not be tough, pretty straight forward.

I assume this harness is meant
To fit between the upfitter box and the engine or straight down behind the wheel well. There are other wire runs that will keep it off the engine if you go that route.

Now for the hard part. Where to ground it to the body. Ground leads are too short. The harness ground end needs to be about two feet longer. This would give you more flexibility.

My idea as of now is to lengthen the ground lead by bolting another wire, probably 6 gauge, to the connector and cover it with heat shrink. Drop it straight done the wheel well to a ground on the frame. Should be last picture.

Thoughts?

 

[🇺🇸BoonesRide22🇺🇸]

View attachment 156923View attachment 156924View attachment 156925

2023 F250 Tremor. Here’s my first attempt with mocking it up to see how it will fit. Easily got to the upfitter wires. Attaching the wires to the harness will not be tough, pretty straight forward.

I assume this harness is meant
To fit between the upfitter box and the engine or straight down behind the wheel well. There are other wire runs that will keep it off the engine if you go that route.

Now for the hard part. Where to ground it to the body. Ground leads are too short. The harness ground end needs to be about two feet longer. This would give you more flexibility.

My idea as of now is to lengthen the ground lead by bolting another wire, probably 6 gauge, to the connector and cover it with heat shrink. Drop it straight done the wheel well to a ground on the frame. Should be last picture.

Thoughts?

Extending the ground was my thought too. Was curious what others had done. Seems to be the best option.

 

[Maine Guide]

Hmm this is turning into more work than I want.

 

[BroncOh]

Any way for the plug pigtails to be a little longer? Looks a little tight in there with all of them together.