mwelch

I got my F-250 back from the Ford Service Department about a month ago (12/23) and haven’t had the issue one single time (it was occurring at least 3-4 times per week before). They tried everything they knew and finally they discovered that the ignition relay switch was loose and all they did was unplug and replug it back in securely. Not one issue since then! Please be sure to have your service dept check this because it’s so simple and completely free (they didn’t even replace the switch, they just plugged the existing one in all the way). Must be an assembly issue. I’m sure there’s a ton of other causes to this same issue, but that’s the easiest/quickest fix and completely solved mine. Hope that helps some of you

2017bluetruck

I'll take a whack at "auxilliary power" the Ford electrical system shuts off power after engine shutdown, controlled by a timer setting. the aux only works with the ignition on. Aux power is supplied at different levels,
"110 V 400 Watt AC Power Point WARNING: Do not keep electrical devices plugged in the power point whenever the device is not in use. Do not use any extension cord with the 110 volt AC power point, since it will defeat the safety protection design. Doing so may cause the power point to overload due to powering multiple devices that can reach beyond the 400 watt load limit and could result in fire or serious injury.
Note: This feature works only when you have the ignition switched on.
Note: This feature has a maximum output of 400 watts when the vehicle is in park (P).
Note: While in drive (D), the maximum outlet output is 300 watts.
Note: When powering electric devices that require more than 10 watts in vehicles equipped with keyless start, the engine must remain running. If the engine is turned off or you switch the ignition to accessory mode, plugged in devices will not be charged.
You can use the power point for electric devices that require up to 400 watts. It is on the instrument panel, and the rear of the center console."

The starting problem may not be related, potential bad switch in brake to low battery. KM

Sterling97

Did you have any issues after doing this? Happen to know where I can find where the ignition relay switch might be loose? I have gone through a ton of batteries trying to fix this issue. Any help is appreciated!