That eyelet hole in the PCB is secured to the sensor body using melted plastic, so yeah.. no Ground connected anywhere on this specific sensor .... I am certain the reason you see that Ground eyelet not being used and the extra capacitor on the "Output" pin basically doing nothing is the fact that the company that fabricates the sensor "TE Connectivity" uses this PCB as a generic for multiple different configurations in other sensors..
Very informative.Hey fellas.. I removed my ring gear/locker assembly and I disassembled the sensor.. I drew this circuit diagram and did some testing..
The operation of this sensor is simple.. it is a Hall Effect Switch operating in current regulation mode... what does it mean? ... when fed with electricity the sensor allows a specific amount of current to circulate when not in the magnetic flux... once in the magnetic flux and when it reaches the threshold it "switches ON" allowing more current to flow.. a very specific value... so this is what I measured..
Not in the magnetic flux (Locker off) = 5.87 ma (milliAmps)
In the magnetic flux (locker engaged) = 14.18 ma (milliAmps)
The way the sensor works in more detail: a positive voltage/current is sent through the "Locker Switch Sense" Pin 2 of the Locker connector (the external connector on the pumpkin) this positive current travels internally on the White cable to Pin 1 on the sensor and the current returns on Pin 3/Blue Cable back to the "Locker Sensor Return" ... the Drive Train Control module measures the current returning from the sensor to determine if the locker is engaged.. So 5.87 milliAmps… Locker not engaged.. 14.18 milliAmps… Locker engaged!!!.. Wohooo!!
Here is a picture of the front of the Hall Effect Switch Chip.. really nothing special.. those numbers "4206" and "9759" in the front most likely indicate the date of manufacturing.. with the 42 on the first row indicating week #42 of the year and the leading "9" on the second row indicating the year as 2019 ... Also, I do not believe this is some sort of mythical.. Obscure, handmade, and individually calibrated sensor. It seems to me like a simple off the shelf Hall Effect sensor. Unfortunately, it has no logo/part number from the manufacturer… if we are willing to look further then we will need to find one with very similar current outputs (5.87ma / 14.18ma) and with the same pinout (depicted on the second photo below)
PINOUT
Just to avoid confusion since you might be asking yourself about the "Output" pin that seems to be unused since it is not connected in any way to the " Drive Train Control module " .. the way this sensor is configured the current flows from the "Input" to the "Ground" pin.. so effectively the "Ground" pin becomes the output and the "OUTPUT" pin is left unused... this configuration forces the Chip to go into the current regulation mode, this is commonly referred as "2-Wire" configuration (this Chip also works in 3 wire configuration mode... where "Input" pin is supplied with a voltage, Ground pin is connected to Ground .. and the "Output" pin generates a voltage proportional to the magnetic flux, this a simpler way to use the sensor) .. the reason to go with 2-wire configuration is that current sensing is less affected by electromagnetic interference compared to voltage transmission on the cable back to the module.. the tradeoff is that current sensing is more difficult to process .. but hey.. these are $50K rigs... so not a big issue to spend more $$ in module development.
In reality, I believe this is an exercise in futility as I imagine that FCA is going to eventually stock this sensor (hopefully a new version that does not fail prematurely like the current one) ... anyway... it was fun to hack this thing and I hope this helps the community ...
Any questions? please feel free to ask!
I believe somebody on this thread mentioned that he/she called them and the company says the sensor is OEM only.. not sold to mere mortals like us.. LOL
Oh yes... I've tried to go through every avenue possible to buy this from TE Connectivity. You cannot buy this.
Whenever you get your new axle, pot the sensor. This will prevent this from happening again until the sensor is available to purchase.
I never bothered with it. Once I installed the Z Locker harness I haven’t had any issues. Used the lockers several times as well. Zero issues.
