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Screens went black!

4345 Views 31 Replies 9 Participants Last post by  FM_Jack
I had my windows tinted in my lightning today, front 2 to match the back and the front glass with 70% ceramic tint. Apparently sometime during or after the tint was finished the instrument cluster screen and the 15 inch screen went black. The truck was still able to be drove to the dealership which is what the tinting company did. This was at the end of the day so nothing has been discovered yet but I have some ideas as to what is going on. Anyone have this issue or something like this happen in the Mach E? The truck was left in accessory mode for the duration of the tinting application. I would say 2-3 hours at least.
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Lots of speculation here, so some clarity.

The Lighting is not a "bleeding edge tech" vehicle, in fact it is pretty dated tech (I, for one, like this about the vehicle... tried & true stuff). Most, if not all of the following will apply to the Lightning.

The 12v battery is responsible for most of the standard vehicle electrical operations we are used to in vehicles. Lights, gages, climate control, stereo etc. Unlike an ICE, an EV has no alternator to maintain the 12v system. A simple DC to DC converter is used in its place taking 400v (nom) from the traction pack and stepping it down to 14.4v (ish) to run the 12v systems and charge the 12v battery.

An EV will not "start" if the 12v battery is dead. Even if your traction pack is charged.

Because the DC to DC converter is a very robust and efficient way to get a lot of 12v power, the 12v "accessory" battery in EVs is often smaller than what you would find in an ICE (plus, it does not have to start an engine). This battery is smaller and less expensive, but unfortunately more prone to failure; much like a motorcycle battery.

The DC/DC converter is always on when the vehicle is on. Otherwise, the vehicles lights and systems would quickly drain the small 12v battery. Want to charge your 12v battery? Turn your vehicle on. NOTE: Tesla drivers who travel know that they should turn on the climate control via the phone app once a month to "wake the car up" while it is stored so the 12v battery does not die. This does not work with all EVs, but hopefully it does with the Lighting.

Most EVs do not run the DC/DC converter with the vehicle off. It would cause too high of a parasitic draw (there are losses involved) on the traction pack.

It is my opinion that EVs should trigger the DC/DC converter when plugged in, to also keep the 12v battery topped off. MOST DO NOT. I travel, and both the GM EV and my Teslas will suffer 12v death if left long enough without being "awakened" as per above.

"12v death" in an EV is much more common than it should be. Fortunately, it is very easy to fix.

A final note for those wanting to do testing on your own DC/DC converters. The big wires are the low voltage side. Seems counter-intuitive, but lower volts = higher amps.
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I believe I read in the owners manual that the lightning charges the 12 volt battery when plugged in as that was an alternative recommendation in the manual for dealing with 12 volt battery issues.

Turns out my trucks issue was an “Audio Control Module”. This was likely damaged by water when they tinted the front window. Service department said when they pulled this module out everything started working again. Thankfully this component is in stock, ready to ship and they have put a major rush on it to get it in as soon as possible. Thanks everyone for your input! As much as I would have rather not had an issue, I have learned a lot about my truck and the workings of the 12 V system through this process. My dealership has been awesome.
That is fantastic! I wish they were all made that way, another example of Ford doing it right. :)
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