Upfitter Wiring Harness Discussion

[Canyon Trekker]

Happy Friday!

Sorry this took so long to get to. I'm in the middle of delivering the grille lights that I make for the F150 Tremor and had a bunch of traveling in Feb for my day job.

I have a sample for the harness in hand and wanted to share for feedback.

This harness uses metripack 630 series connectors that are rated for 46A. the 6 main circuits are 10ga wire. the 4 additional PTO and B+ circuits are 16ga.

The main harness connectors are the male side of the connection so that the end caps are useable for unused circuits. the pigtails would be included to put on whatever accessory you are hooking up.

I think for production, I'd make the positive legs a little longer to get them more accessible and move the heatshrink on the grounds a little further back to make each connection a little more flexible and independent.

This unit has 3 separate ring terminals for the grounds. for production, they likely would be consolidated to 2 connectors

the production version would use a braided split loom sheathing like I have on the F150 version. the corrugated shown was just what was on hand.

this harness as shown would be sold for $150 + shipping

Let me know your thoughts.

Thank you,

Cory
View attachment 147819


View attachment 147820

here's what the braided wire loom looks like.
View attachment 147821

This looks very nice. My truck is already fully wired, or I would take you up on a set. One suggestion, for those that do not have a crimper tool or crimp terminals, perhaps include the terminals, or you could even offer a kit with both. (Higher price of course.) They will need a method to tie these to the original upfitter wires.

Thanks for doing this project.

 

[MTUcrash]

CT = current transfomer. It measures the current flowing in a wire, and is used by the battery management system to understand the power draw from the battery and its state of charge. If you bypass the CT, the computer doesn't know power is being consumed.

Exactly what he said!
The black circular plastic device that the battery ground cable runs through. Also, if going through it, make sure it goes through in the same direction as the ground cable.

 

[CADUCKHUNTER]

Very interested when the CT Thing gets figured out

 

[DTX2023Tremor]

Happy Friday!

Sorry this took so long to get to. I'm in the middle of delivering the grille lights that I make for the F150 Tremor and had a bunch of traveling in Feb for my day job.

I have a sample for the harness in hand and wanted to share for feedback.

This harness uses metripack 630 series connectors that are rated for 46A. the 6 main circuits are 10ga wire. the 4 additional PTO and B+ circuits are 16ga.

The main harness connectors are the male side of the connection so that the end caps are useable for unused circuits. the pigtails would be included to put on whatever accessory you are hooking up.

I think for production, I'd make the positive legs a little longer to get them more accessible and move the heatshrink on the grounds a little further back to make each connection a little more flexible and independent.

This unit has 3 separate ring terminals for the grounds. for production, they likely would be consolidated to 2 connectors

the production version would use a braided split loom sheathing like I have on the F150 version. the corrugated shown was just what was on hand.

this harness as shown would be sold for $150 + shipping

Let me know your thoughts.

Thank you,

Cory
View attachment 147819


View attachment 147820

here's what the braided wire loom looks like.
View attachment 147821

I think the main thing to know is how do I give you my money?

 

[Canyon Trekker]

Exactly what he said!
The black circular plastic device that the battery ground cable runs through. Also, if going through it, make sure it goes through in the same direction as the ground cable.

Very important. Good that you noted direction.

 

[Maine Guide]

I think the main thing to know is how do I give you my money?

beat me to the question, send me a pm or what ever it is and I will get you some funds in your virtual pocket or what ever you call it. Praise Jesus. And thanks for going through all this effort.

 

[Momma’s Trim!]

Yes, still interested when final version is decided on.

 

[Cblaxx19]

CT = current transfomer. It measures the current flowing in a wire, and is used by the battery management system to understand the power draw from the battery and its state of charge. If you bypass the CT, the computer doesn't know power is being consumed.

thank you for the clarification. i don't believe that exists on the F150, at least i haven't seen it.

Exactly what he said!
The black circular plastic device that the battery ground cable runs through. Also, if going through it, make sure it goes through in the same direction as the ground cable.

could you take a picture of it and share it? a quick google search didnt yeild a pic. (i didnt dive into the youtube videos yet).

the ground legs are currently 24" long. is that enough length to go from the positive upfitter leads, through the CT, and to the battery?

another option is to ground to a body mount, assuming the negative leads make it through the CT and to a nearby body ground point. but battery negative would be better.

 

[MTUcrash]

thank you for the clarification. i don't believe that exists on the F150, at least i haven't seen it.

could you take a picture of it and share it? a quick google search didnt yeild a pic. (i didnt dive into the youtube videos yet).

the ground legs are currently 24" long. is that enough length to go from the positive upfitter leads, through the CT, and to the battery?

another option is to ground to a body mount, assuming the negative leads make it through the CT and to a nearby body ground point. but battery negative would be better.

Yes, I will get a pic. For mine, I grounded my accessories to the 6mm body ground bolt near the battery on the fender area. The pic will show that as well. It also has a main body ground cable going through the sensor to the battery from this bolt. I believe the f150s are even more sophisticated in battery monitoring with the power cable going directly through a sensor with an actual connection rather than a Hall effect sensor.

 

[Maine Guide]

Correct me if I’m wrong, the ct is not for reading the grounds it is for the amount of current draw so it will have to have a power source going through it which I feel the uplifted switches are all ready part of the existing power wiring which would be monitored already?

 

[overland]

The CT reads the current coming back into the battery via the negative terminal (ground) vs reading current going out (positive side). So it depends if you’re connecting the upfitter grounds directly to the battery or not. If you’re using a ground point on the frame, then no problem, that current will be seen through the existing battery negative cable. But if you connect directly to the battery without going through the CT then the current won’t be seen.

 

[Maine Guide]

How can the current not be seen through the lifter switches providing the power, regardless where the ground is. A ground is a ground and I see no difference whether it is body ground or battery. The up lifter switches would have the monitoring for power provided regardless if power was to bleed to ground?

 

[MTUcrash]

How can the current not be seen through the lifter switches providing the power, regardless where the ground is. A ground is a ground and I see no difference whether it is body ground or battery. The up lifter switches would have the monitoring for power provided regardless if power was to bleed to ground?

It is monitoring the current flowing back into the negative battery terminal, not measuring current out of the positive. So, no, the upfitter relay outputs are NOT part of that flow unless the negative current flows through the sensor - either by grounding to the frame (and then the frame ground is already going through the sensor), or with wires going directly through the sensor with the other ground cables.

 

[MTUcrash]

It is monitoring the current flowing back into the negative battery terminal, not measuring current out of the positive. So, no, the upfitter relay outputs are NOT part of that flow unless the negative current flows through the sensor - either by grounding to the frame (and then the frame ground is already going through the sensor), or with wires going directly through the sensor with the other ground cables.

See pictures of the sensor (black plastic ring with sensor wire connected to it and ground cables going through it) along with the main body ground location I used.

 

[Cblaxx19]

See pictures of the sensor (black plastic ring with sensor wire connected to it and ground cables going through it) along with the main body ground location I used.View attachment 147886View attachment 147887View attachment 147888

Ok. Based on these photos, it doesn’t look like there is room to run anything g else through the CT. So using the body ground point right there seems like the best option.

Is 24” of length adequate to get from the upfitter wires to that ground point?

I wish I had access to a super duty to just see all this stuff myself.

Thanks for all the info

 

[DTX2023Tremor]

Ok. Based on these photos, it doesn’t look like there is room to run anything g else through the CT. So using the body ground point right there seems like the best option.

Is 24” of length adequate to get from the upfitter wires to that ground point?

I wish I had access to a super duty to just see all this stuff myself.

Thanks for all the info

I suggest a separate thread with a subject looking for a 2020+ owner in your area who can meet up so you can get measurements and photos or see if your local dealer will let you pop the hood on one in the lot. Others have had success with the first approach and mixed success with the dealer approach.

 

[MrFancypants]

Correct me if I’m wrong, the ct is not for reading the grounds it is for the amount of current draw so it will have to have a power source going through it which I feel the uplifted switches are all ready part of the existing power wiring which would be monitored already?

That’s not really how DC systems work. Technically electrons flow out the negative terminal and into the positive terminal, not the other way around. The term “ground” isn’t the same as an AC system.

It’s very difficult for an ECM to monitor current directly because it’s not connected directly to every circuit and that would require a lot of heavy gauge copper. Control circuits with low current (small wires) trigger power circuits (big wires) via relays. It would be a lot easier to measure voltage but unfortunately that is a lousy indicator of battery performance. Enter the current transformer, but where to put it?

It’s easier/cheaper to monitor the ground path because that is a common reference for every circuit. While there are only 2 wires coming off the battery ground, they are actually carrying all the power coming out of the battery!

Which leads me to another point. Wire sizing isn’t just about current but about length and continuous draw (time). You will notice the surprisingly small gauge wires from the battery to the chassis (going through the CT). That’s because the run is very short. The chassis is a giant conductor with many small arteries connected at various points. It can handle a lot of current. The ground wire and lug used in this harness looks really oversized.

 

[Cblaxx19]

That’s not really how DC systems work. Technically electrons flow out the negative terminal and into the positive terminal, not the other way around. The term “ground” isn’t the same as an AC system.

It’s very difficult for an ECM to monitor current directly because it’s not connected directly to every circuit and that would require a lot of heavy gauge copper. Control circuits with low current (small wires) trigger power circuits (big wires) via relays. It would be a lot easier to measure voltage but unfortunately that is a lousy indicator of battery performance. Enter the current transformer, but where to put it?

It’s easier/cheaper to monitor the ground path because that is a common reference for every circuit. While there are only 2 wires coming off the battery ground, they are actually carrying all the power coming out of the battery!

Which leads me to another point. Wire sizing isn’t just about current but about length and continuous draw (time). You will notice the surprisingly small gauge wires from the battery to the chassis (going through the CT). That’s because the run is very short. The chassis is a giant conductor with many small arteries connected at various points. It can handle a lot of current. The ground wire and lug used in this harness looks really oversized.

relative to the wire sizing comment. I used 10 ga on the grounds to match the 10ga on the positive leads that I was told the upfitter wires are. also, most of the wire sizing tables I've looked at call for 10ga wire for 35-50A in a wire length of 0-4ft.

I don't want to undersize and have issues, so figured to err on the side of conservatism. dropping a size or 2 on wire ga doesn't have a very big impact to the overall harness cost either. so im not driving a bunch of unnecessary cost into the harness by being conservative.

 

[Canyon Trekker]

That’s not really how DC systems work. Technically electrons flow out the negative terminal and into the positive terminal, not the other way around. The term “ground” isn’t the same as an AC system.

It’s very difficult for an ECM to monitor current directly because it’s not connected directly to every circuit and that would require a lot of heavy gauge copper. Control circuits with low current (small wires) trigger power circuits (big wires) via relays. It would be a lot easier to measure voltage but unfortunately that is a lousy indicator of battery performance. Enter the current transformer, but where to put it?

It’s easier/cheaper to monitor the ground path because that is a common reference for every circuit. While there are only 2 wires coming off the battery ground, they are actually carrying all the power coming out of the battery!

Which leads me to another point. Wire sizing isn’t just about current but about length and continuous draw (time). You will notice the surprisingly small gauge wires from the battery to the chassis (going through the CT). That’s because the run is very short. The chassis is a giant conductor with many small arteries connected at various points. It can handle a lot of current. The ground wire and lug used in this harness looks really oversized.

The theory here is correct with a few caveats related to our trucks. I believe we are overthinking this sensor and its purpose. I admit, I got caught up in it as well until I read the manual.

The sensor is what is called a Hall Device, basically a DC current sensor without direct connection to the circuit. AC/variable current would typically be sensed through a transformer or tap. I believe the Hall device is merely monitoring the state of charge from the alternator/generator. The alternator converts AC to DC and then is fed to the batteries as a DC, to regenerate a charge. It's also (obviously) to run the vehicle accessories while in operation. The current connection path is through this sensor.

The Hall device can sense both negatively flowing, and positively flowing current. It is a sensor to determine charge or discharge, which is fed to the BCM to determine health. Most all of the DTCs related to this device are also related to generation troubleshooting tips. (In the maintenance section of the complete manual.)

As for the hook-up in the truck, it would not be necessary to run any cables through this sensor for operating any added accessory. Using the chassis ground is sufficient and frankly, does not directly determine state of charge with generation. To emphasize this point, if you have dual batteries, only one battery is hooked up through this sensor. And there is good reason. The other battery is connected directly to the engine block, which makes it electrically the same as the chassis. The current generated by the alt/generator will be felt for both batteries while charging, through this sensor, since the chassis and engine block are electrically at the same point.

Here's an excerpt from the manual:

Battery Current Sensor

The battery current sensor which only monitors current flow in/out of the battery, The battery current sensor is attached to the battery negative

cable. It is supplied a 5-volt reference voltage and a ground from the BCM. The battery current sensor is a Hall-effect sensor that supplies an

analog feedback signal to the BCM. The BCM reads the battery current sensor feedback voltage to determine how much current is flowing

through the battery ground cable. The BCM uses this information for battery state of charge.

One more tid-bit from the manual:

PINPOINT TEST I : BATTERY CURRENT SENSOR FAULTS

Refer to Wiring Diagrams Cell 12 for schematic and connector information.

Normal Operation and Fault Conditions

The BCM monitors the battery state of charge using the battery monitoring sensor attached to the negative battery cable. Battery voltage is hardwired to the battery monitoring sensor and data is transferred from the battery monitoring sensor to the BCM via a LIN circuit.

DTC Fault Trigger Conditions

DTC Description Fault Trigger Condition

BCM

B11DB:02...
...and a whole lot more troubleshooting points after this related to charging DTCs.


Here are some schematics showing the electrical position of the sensor. Schematic 2 does not show the sensor, but it is connected around the two wires showing connection to the chassis/negative battery post of only one battery. (Passenger side) The other negative terminal is hooked directly to the engine block.

I hope this helps clarify, bottom line: Hook the upfitter ground cable directly to the chassis or whichever negative battery stud that's convenient.

 

[Alpoba]

I hope this helps clarify, bottom line: Hook the upfitter ground cable directly to the chassis or whichever negative battery stud that's convenient.

Im still not fully clear on why not hook up to the battery end of that very ground cable then. I did so for one of my upfitters drawing less than 1 watt.