Upfitter Wiring Harness Discussion

[Canyon Trekker]

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.

You're perfectly fine. It doesn't matter where you hook it up, chassis, or direct to the battery. I was simply stating that the OP doesn't need to run a ground through the Hall sensor. The Hall sensor is only for a state of generator charge/discharge, irrelevant to the accessory hookup.

Nice wrap job by the way...

 

[Alpoba]

You're perfectly fine. It doesn't matter where you hook it up, chassis, or direct to the battery. I was simply stating that the OP doesn't need to run a ground through the Hall sensor. The Hall sensor is only for a state of generator charge/discharge, irrelevant to the accessory hookup.

Nice wrap job by the way...

Thanks, i probably have the longest extension harness there is. But my whole annoyance was having to dive into the bay so now i can at least stay out of it completely to work on my hook-ups

And thanks for confirming on ground connection. I got lost in the sauce in the earlier posts.

 

[MrFancypants]

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.

Hats off to you. Always good to have someone to take the time and RTFM

i still wouldn’t attach directly to the battery, if for no other reason than it’s cleaner. It would also be interesting to see how this would impact (or not) the behavior of BCP.

 

[overland]

Thanks, i probably have the longest extension harness there is. But my whole annoyance was having to dive into the bay so now i can at least stay out of it completely to work on my hook-ups

View attachment 147958

And thanks for confirming on ground connection. I got lost in the sauce in the earlier posts.

Just seeing your connectors there - what do people think about using lever nuts in the engine bay? Any concerns about corrosion over time?

 

[overland]

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.

View attachment 147924

View attachment 147925

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

Forgive me if I'm misinterpreting your post, but as I'm reading it you seem to be thinking of State of Charge as just whether or not the battery is being charged. SOC is rather a snapshot of the current charge level - is it 40%, 80%, etc. That can be estimated via voltage level, or determined more accurately by measuring the current flow with a meter (hall meter or a shunt). If you're using a current meter, you obviously want to know everything going in and out of the battery - if you don't, then what's the point? So no, you don't want to bypass the sensor by connecting things directly to the battery without going through it. That said, I doubt that most accessory usage will have a large impact on those calculations, so doing so probably isn't going to mean much. However, if you're bypassing the sensor with a large amperage draw, or perhaps a lengthy one, then obviously the actual and calculated SOC of the battery are going to diverge. What happens then I can't say - perhaps an engine light if the truck senses a battery voltage that's lower than what it should be per the calculated SOC? I doubt you're getting stranded, but maybe it's possible in an extreme situation.

Regardless, it's easy to just connect your grounds to the chassis and then you don't have to worry about it. Easier anyway. As to why Ford only measures the current on the primary battery, I suspect it's because they just don't care all that much about the secondary. That is, if you take care of the primary's charge level, the secondary will follow along well enough. Unless it's gone bad - I've had that happen with a bank of LFP house batteries where half of them were unknowingly damaged and I went a night without power despite my trusty Victron kit insisting I was at 60%.

I suspect, too, that ford doesn't care too much about absolute accuracy on this front, since they have to account for external charges and drains anyway. I mean, if someone connects a battery maintainer to the terminals, the sensor obviously isn't picking that up, nor if someone did the same with a portable winch or something. So maybe the truck may not get all that upset when the SOC isn't what it thinks.

Still, why tempt fate.

 

[Alpoba]

Just seeing your connectors there - what do people think about using lever nuts in the engine bay? Any concerns about corrosion over time?

Are you asking me directly or what others think about my connectors?

on a personal level i have zero corrosion worries; where i place the harness end and how i have it wrapped up and knowing that the spot has no water coming in contact with it at any time, led me to these connectors.

But if i was designing a commercial solution for others to use such as the one being discussed on this thread, i would go for a waterproof type of connector.

 

[Maine Guide]

It’s a good thing I did not bring up how the winch draws on the primary

 

[Canyon Trekker]

Forgive me if I'm misinterpreting your post, but as I'm reading it you seem to be thinking of State of Charge as just whether or not the battery is being charged. SOC is rather a snapshot of the current charge level - is it 40%, 80%, etc. That can be estimated via voltage level, or determined more accurately by measuring the current flow with a meter (hall meter or a shunt). If you're using a current meter, you obviously want to know everything going in and out of the battery - if you don't, then what's the point? So no, you don't want to bypass the sensor by connecting things directly to the battery without going through it. That said, I doubt that most accessory usage will have a large impact on those calculations, so doing so probably isn't going to mean much. However, if you're bypassing the sensor with a large amperage draw, or perhaps a lengthy one, then obviously the actual and calculated SOC of the battery are going to diverge. What happens then I can't say - perhaps an engine light if the truck senses a battery voltage that's lower than what it should be per the calculated SOC? I doubt you're getting stranded, but maybe it's possible in an extreme situation.

Regardless, it's easy to just connect your grounds to the chassis and then you don't have to worry about it. Easier anyway. As to why Ford only measures the current on the primary battery, I suspect it's because they just don't care all that much about the secondary. That is, if you take care of the primary's charge level, the secondary will follow along well enough. Unless it's gone bad - I've had that happen with a bank of LFP house batteries where half of them were unknowingly damaged and I went a night without power despite my trusty Victron kit insisting I was at 60%.

I suspect, too, that ford doesn't care too much about absolute accuracy on this front, since they have to account for external charges and drains anyway. I mean, if someone connects a battery maintainer to the terminals, the sensor obviously isn't picking that up, nor if someone did the same with a portable winch or something. So maybe the truck may not get all that upset when the SOC isn't what it thinks.

Still, why tempt fate.

Glad to see you understand State of Charge, your first two lines are correct up to "or determined more accurately by measuring the current flow with a meter (hall meter or a shunt)" You also make goods points elsewhere and spot on about batteries in parallel, one can be bad, and you wouldn't necessarily know it. (Please read to the end, more surprising info.)

Not to get too far off subject here, the question is: can a ground wire be hooked up to the battery post in lieu of the chassis? The answer is unequivocally yes. If this weren't true, the second battery would not be connected directly to ground via the engine block, and they wouldn't have put studs on the battery connectors for optional connections. Current is drawn by any accessory equally from both batteries. (More on the current sensor below)

The rest of the story for the curious:
SOC is the state of the batteries at any given time. SOC is a battery indicator, not a condition of operation per-se. You are also correct, the system monitors voltage to determine SOC, not current. If you ever have a DTC or fault, the first rule of order is to check the SOC of the battery. Where I think we're getting off track here is confusing SOC with how the current sensor works and its purpose. The current sensor cannot measure a State of Charge, only whether the alt/gen is functioning properly to bring the SOC back to normal. (More on this later) It's also possible that the system can detect a sudden or higher than normal draw and trigger a DTC via the current sensor, but that would not make sense since it would also be drawing from the second battery as well and not monitored.

From the manual:
Charging System Warning Indicator
The charging system warning indicator is controlled by the IPC based upon the battery low state of charge message received from the GWM over
the HS-CAN3. The GWM receives the battery low state of charge message from the BCM over the HS-CAN1. When a fault is detected in the
charging system, the BCM sends the IPC the battery low state of charge message to illuminate the charging system warning indicator.

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. (See next paragraph after the acronym descriptions for hypothetical conditions.)

A whole herd of acronyms to say the computers are monitoring the charge state.
battery energy control module (BECM); parameter identification (PID); Diagnostic Trouble Codes (DTCs); Body control module (BCM); IPC: Independent Plausibility Checker; GWM Gateway module; CAN- Many types, system communication buses.

What if:
What if the current sensor was actually used in the shutdown scheme. How would it work? If you had a 1-million-amp hour battery, and continuously drew 100 amps, the state of charge would take a long time to change. Voltage levels would remain stable for many hours and whatever you were operating would continue to run. However, if you had a 100 amp-hour battery with 100A draw, it would instantly change and the BCM would try to shut the system off, you may get a DTC code. The Hall device would sense 100A draw in either condition. It would not set this as a condition to shut down, it would determine the voltage drop or SOC as the condition to shut down. It wouldn't care how much current is drawn, but rather how good is the State of Charge as it is being drawn down. A Hall sensor can only detect current, not voltage. As the battery goes down in voltage, the computers would respond to the voltage change, not the current change.

In the old days, battery/charging systems measurement was accomplished through a shunt (as you also mentioned), the meter could show both negative and positive current on an analog scale. It was simple to look at the meter while running to determine if the battery was taking a charge. (Or at least the alternator was generating enough voltage to charge the battery)
When the vehicle was off and a load applied, (headlights) it always read negative. The human was the computer to determine its health.

Today technology is leaps and bounds past those days. The Hall sensor is a very efficient way to measure current via a FET circuit, drawing virtually no current to operate and no loss through a shunt. If a load is turned on and the battery drops to a given level, things start to shut off. It doesn't matter where the source is drawing from, the battery (or batteries) will still go low, and the multitude of sensing points will pick that up. These trucks are quite literally a computer on wheels.

There are countless times the SOC terminology is called out in the troubleshooting guide as a condition of the DTC, not being a DTC itself. If there was a short, then you would get a DTC, again, first order of troubleshooting in most all cases of a voltage related DTC, is to check the batteries for connections, shorted wires. SOC, etc. It doesn't have to be sensed through the current sensor; it's monitored via voltage by the BECM/BCM...

Your last couple of paragraphs are perfect timing as to my next point and reason for another upgrade to the truck, two batteries are on order, will have them tomorrow. Why? My original batteries have been on a maintainer for a while now simply because 6 months ago, I knew they were near the end of their lives (Corrosion) and I don't drive it that often. (Sadly) Yesterday I went out to check on the state, popped the hood, and there it was. A battery symbol on the charger/maintainer with a red X through it. Why? The manual says, " battery will not hold charge". So, I checked them manually, the driver's side battery is toast. Ironically, the truck starts and runs normal and NO DTCs.

The Noco is smarter than the truck computers.

Sorry for the long-winded reply.

 

[Cblaxx19]

after all of this discussion, i don't think any changes need to be made to the harness design. So i will work on setting up a preorder page on my site and post back here once it is live.

 

[LT75]

Can anyone with a ‘23 or ‘24 tell me where they are bolting their ground too? On the ‘22 the ground bolt was next to the passenger battery right by the upfitter harness. On the ‘24 the ground is on the drivers side now by that battery on the opposite side of the upfitter harness.

 

[Cblaxx19]

Preorders are now open for the Upfitter harness. This the preorder window will be open until at least 4/1/24. At that time, based on the order demand, ill place my orders for materials. Estimated shipment is 4-6 weeks from 4/1.

harness order link: https://cblightingdesigns.myshopify.com/products/superduty-upfitter-wiring-harness

also, if you don't plan on using all of the connections right away, here's the link to the caps that you can add to your order: https://cblightingdesigns.myshopify.com/products/upfitter-wiring-harness-cap-for-unused-plugs

 

[kruschev]

Preorders are now open for the Upfitter harness. This the preorder window will be open until at least 4/1/24. At that time, based on the order demand, ill place my orders for materials. Estimated shipment is 4-6 weeks from 4/1.

harness order link: https://cblightingdesigns.myshopify.com/products/superduty-upfitter-wiring-harness

also, if you don't plan on using all of the connections right away, here's the link to the caps that you can add to your order: https://cblightingdesigns.myshopify.com/products/upfitter-wiring-harness-cap-for-unused-plugs

Just ordered, thanks!

 

[yArdbird]

Preorders are now open for the Upfitter harness. This the preorder window will be open until at least 4/1/24. At that time, based on the order demand, ill place my orders for materials. Estimated shipment is 4-6 weeks from 4/1.

harness order link: https://cblightingdesigns.myshopify.com/products/superduty-upfitter-wiring-harness

also, if you don't plan on using all of the connections right away, here's the link to the caps that you can add to your order: https://cblightingdesigns.myshopify.com/products/upfitter-wiring-harness-cap-for-unused-plugs

Admittedly late to the discussion, but seems like a great product. Curious about the PTO and B+ wires. I have a BD high idle switch installed, but regardless don’t anticipate ever using anything beyond the upfitter wires. Appears to be all one harness, is that correct? Will there be an option to just extend the upfitter wires or would I simply not connect the other wires mentioned and bury the connectors under the fuse box?

Apologies for asking what are probably obvious questions to most. Thank you in advance for your response.

 

[Socal]

Preorders are now open for the Upfitter harness. This the preorder window will be open until at least 4/1/24. At that time, based on the order demand, ill place my orders for materials. Estimated shipment is 4-6 weeks from 4/1.

harness order link: https://cblightingdesigns.myshopify.com/products/superduty-upfitter-wiring-harness

also, if you don't plan on using all of the connections right away, here's the link to the caps that you can add to your order: https://cblightingdesigns.myshopify.com/products/upfitter-wiring-harness-cap-for-unused-plugs

Just ordered

 

[Canyon Trekker]

Admittedly late to the discussion, but seems like a great product. Curious about the PTO and B+ wires. I have a BD high idle switch installed, but regardless don’t anticipate ever using anything beyond the upfitter wires. Appears to be all one harness, is that correct? Will there be an option to just extend the upfitter wires or would I simply not connect the other wires mentioned and bury the connectors under the fuse box?

Apologies for asking what are probably obvious questions to most. Thank you in advance for your response.

Hi @yArdbird , I assume you are asking if the PTO and B+ wires can be tucked under, correct? If so, it's best to order the termination for the two connectors and then tuck them away. They are not required if you're not adding an accessory. The high idle kit I assume is already installed; it doesn't require anything additional. I use my B+ wire to run things I want hot at all times. I just hooked it up to one of the passthrough wires into the cab.

 

[Painless]

Ordered!

 

[🇺🇸BoonesRide22🇺🇸]

Ordered!

 

[In Production]

Ordered,

 

[cntyguy]

Ordered. Thanks for putting this together for us SD owners! Will clean up the bay a bit.

 

[CADUCKHUNTER]

Ordered also