Confirmation that the door latch switch is a Body Ground?

[chiko]

That is how I read the 2022 Maverick schematic. That the GN-VT (drivers/LH side still can't find exactly the passenger side) is a body ground switch that is closed circuit when the door is opened.

I am trying to add some additional courtesy lamps to the footwell when the door is opened. I will receive a better battery tomorrow so this will be less of an issue. It makes sense in my mind that the BMS (battery management system) would just manage which loads would get a hot and that my intermittent courtesy lamps won't light because the BMS has decided to cut the hot but still let the switch control to ground.

Any insight on Driver Door Ajar SW vs Driver Door 2nd Ajar SW (GY-OG Grey-Orange)? I am guessing it has something to do with opened/closed/mostly closed but not complete. I would like to trigger these lights on anything but fully closed.

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[chiko]

Tested with Battery Negative disconnected just in case.
Tapped pin 29 & 32 on the BCM harness and confirmed they are body GND but unfortunately I got continuity with the doors closed, not open as I expected. I can do something with a relay, I guess.

 

[BlueSpec1]

Looking at the diagram and description I guess the BCM has a pullup circuit that draws down the BCM's voltage with the door switches closed. The circuit in the BCM detects Close/Ajar this way.
Manual as usual doesn't give may clues.

I wonder if a SSR could be triggered by the door switch input to the BCM if there's 12V on those pins with the switches open.

I've used a small SSR on a BCM wire so I didn't affect the voltage.
KF0604D Relay Solid State, 32 VDC Input, 4 Amp, 60 VDC Output, 4 Pin, 1.5" - 175222

My electronics knowledge is very, very rusty so you should double check how these work.

 

[chiko]

Am I just too dumb to figure this out? I have above average understanding of electrical stuff, which aint saying much.
I need a constant HOT to drive the lamps independent of the key switch position. Door open = Lights ON. If the door had a body GND, then Door Open = Circuit closed and I am golden.

In my thought process I could add a relay. But then I need a constant HOT to energize the relay pin and to depend on the Ford door circuit to provide the control side of the relay to keep the lamps OFF and put the lamp load on the NC pin. But this creates a leaching load all the time the doors are closed which is almost always. In my mind, I vaguely thought of a schematic with two relays so that either door could trigger. But as I worked through the schematic, I recognize that I was dumb and that it would only trigger on both doors. I am not committed to either door being a trigger and could run the circuits independently.

 

[BlueSpec1]

Is there a voltage on the BCM pins 23, 32 when its door is open?

 

[chiko]

Is there a voltage on the BCM pins 23, 32 when its door is open?

Not sure. Battery Neg was disconnected and I was doing continuity test on the front side of the connector to the BCM which was disconnected from the BCM proper.

If I had to guess, there would be 12V on the circuit when the door is closed and the connector plugged to the BCM but no potential from PIN to GND.

Probably not going to try it but if the door is open then that circuit would still have potential to GND and I could use that to drive the lamps but probably also defeating all the Door Ajar sensors. Too much uncertainty.

 

[BlueSpec1]

I was thinking the opposite, that would have 0 volts with door closed, +12v with door open.
I haven't checked, so I don't know.

The circuit wiring reminds me of how RTUs/PLCs status inputs can be wired.

 

[chiko]

The circuit wiring reminds me of how RTUs/PLCs status inputs can be wired.

I appreciate the feedback. I am pretty sure that PLC stands for Programmable Logic Controller. What that is, is beyond me. RTU I cannot even begin to guess.

 

[chiko]

I tried to again test tonight to see if the footwell lamps were too bright and I got total failure on the after-market lamps. Factory courtesy still worked. I am going to redo the after-market harness tomorrow and take some measurements. Most importantly I will be soldering all connections outside the confines of the vehicle, wire from the load back to source and make the final connection with a crimp as is my understanding of best practice.

In case I forget, the selected Orange LED strip, for which Amazon is not showing in my history, had a pretty poor adhesive strip.

I have pictures for the process but want to get a final result and then DIY up to it, including mistakes.

 

[chiko]

Finished Product - Not nearly as bright as the photos would suggest but definitely courtesy level brightness, not ambient.

I back stabbed Pin 17 courtesy light in the BCM connector with 20 AWG solid and then connected 24 AWG stranded to each light strip.

I have no insight on how to remove the connectors from the BCM except that you pull the handle to the outboard side and you need to release the catch to do that. What makes that catch release the latch is still difficult. Re-install is pretty easy in that you should be able to press medium firm on the connector and it will move the latch inboard and then finally lever into place. Removing the backside of the connector (mine is white) to expose the backside where you can pin in was pretty easy. I used zip-ties to connect my tap to the pin 17 wire directly to keep the back stab in place with a tiny zip tie and then a larger zip tie to keep my tap attached to the harness for the connector.

I got the light strip from Amazon recently but it does not show in my order history so I cannot provide a direct link. It's about 1/4" wide and maybe 10' long for <$20. You can cut to length as desired and there are solder points about every 4 in.

Many mistakes were made in this project but the worst for me was trying to tap into the door connector: A) Body Ground when door is closed but nothing when door is open; so useless. B) I cannot get the dust/weather protector back on. It was a struggle to get it off and I tried jacking up the door and releasing the lower and middle hinges to provide more access but ultimately had to give up lest I crank the upper hinge. I guess I will take it to a body shop that will have more experience.

 

[BlueSpec1]

I cannot get the dust/weather protector back on.

That is a very tight spot to work in.
Those flexible EPDM tubes won't go on the plastic grommet base till it is out of the door hole.
Then can fit the flexible tube onto it and press the base back into the door.

Something like one on a Escape liftgate:

https://www.mavericktruckclub.com/forum/threads/door-harness-wont-sit-flush-anymore.43992/

 

[chiko]

Today I confirmed that the overhead map lights do NOT activate the footwell lamps. Fine for my purposes. The map lights must have a separate hot activated by the switch while the courtesy function is driven by the BCM.

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