Dead battery after disconnecting inline OBDII module?

[stilbo]

I hope I didn’t brick the electronics in my 2021 XLT.

I decided to see why the OBDII port was so difficult to attach my Snap On analyzer so I started poking around under that side of the dash and found a FoMoCo module connected inline with the port.

The module and extra wiring is held in place with five zip ties which definitely doesn’t look to be a factory installation.

I snipped the zip ties to get a better look at what’s going on and disconnected one side then realized that there’s an inline OBDII connector on the truck harness side plus another bundle of taped wires going directly into the truck side harness. The third wire bundle goes to the actual OBDII output connector…

I reconnected the module on the truck harness side then started the truck and proceeded to look at the truck functions on the analyzer with no problems then shut off the truck.

Yesterday I went to start the truck and it was dead… zero things happening with key on.
I haven’t checked battery voltage or jump started it yet.

The truck was a company fleet vehicle and when I first saw the module I thought it might be a means to track the vehicle speed, braking etc and possibly a GPS locator…
I read up on possibilities last night and found that what I have might be either a Smart Data Link Module (GWM / Gateway Module) or a Ford Plug-In Telematics/Modem Module.
I’m thinking that the Battery Management System might have gotten discombobulated?

If anyone has any sage advice as to just what this module is and what might have happened when I disconnected it please reply…

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[stilbo]

BTW: The AGM battery is only four months old, had a surface charge output of 13.4 volts a week ago and was installed when I bought the truck four months ago.

 

[stilbo]

BTW: The AGM battery is only four months old, had a surface charge output of 13.4 volts a week ago and was installed when I bought the truck four months ago.

 

[HeatXfer]

Pictures would help (me, anyway)

 

[RangerBill]

I hope I didn’t brick the electronics in my 2021 XLT.

I decided to see why the OBDII port was so difficult to attach my Snap On analyzer so I started poking around under that side of the dash and found a FoMoCo module connected inline with the port.

The module and extra wiring is held in place with five zip ties which definitely doesn’t look to be a factory installation.

I snipped the zip ties to get a better look at what’s going on and disconnected one side then realized that there’s an inline OBDII connector on the truck harness side plus another bundle of taped wires going directly into the truck side harness. The third wire bundle goes to the actual OBDII output connector…

I reconnected the module on the truck harness side then started the truck and proceeded to look at the truck functions on the analyzer with no problems then shut off the truck.

Yesterday I went to start the truck and it was dead… zero things happening with key on.
I haven’t checked battery voltage or jump started it yet.

The truck was a company fleet vehicle and when I first saw the module I thought it might be a means to track the vehicle speed, braking etc and possibly a GPS locator…
I read up on possibilities last night and found that what I have might be either a Smart Data Link Module (GWM / Gateway Module) or a Ford Plug-In Telematics/Modem Module.
I’m thinking that the Battery Management System might have gotten discombobulated?

If anyone has any sage advice as to just what this module is and what might have happened when I disconnected it please reply…

The Gateway module is factory and part of the OBDII port. The telematics module is mounted on the passenger side of the truck, behind the glovebox.

Measure the battery voltage. Jumpstart the truck and read the battery voltage with the truck running. The alternator may not be charging, or its 225 amp fuse blown. I don't think that what you did under the dash caused the issue.

 

[stilbo]

Thanks RangerBill!
I jump started it this morning
It started and ran no problem
I have a 12VDC accessory port (Cigarette lighter) voltage meter in it and while running it shows 14.2 volts..
I only let it run for a minute (in shop) to get that reading.
When shut off battery voltage at the battery terminals shows 4.1 VDC.
I have it on a 2 amp charger now.
Being that the battery drained overnight after disconnecting and reconnecting the module, I tend to associate anything that would drain the battery with my possible misdeed.
I have a 2016 Mustang GT and 2016 Expedition and neither of them have anywhere near as many crazy battery connections withbreakers, fuses and relays?)
At this point I’m thinking that something drained the battery…
But….
I may have had a moron moment yesterday when looking at the engine off/key on status on my analyzer and simply left the key on…
I’ve done dumber things over the last 71 years.

 

[stilbo]

Pictures would help (me, anyway)

 

[stilbo]

This website doesn’t accept an “IMG” image file which is an iPhone image file…
Weird.
Maybe everyone on 5G has Android phones?

 

[AzScorpion]

This website doesn’t accept an “IMG” image file which is an iPhone image file…
Weird.
Maybe everyone on 5G has Android phones?

I have an iPhone and have no problems loading images. You can copy and paste them from your phone or if using a web browser (I use Safari) I email them to myself, save to downloads folder then either copy and paste them or use the Attach Files tab in the lower left corner.

If you need to convert pictures or videos this is a good free converter site. At the top of the page you'll see Convert and you can select from the dropdown menu.

https://convertio.co/jpg-gif/

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