Flat battery after every thunderstorm

[JohnT]

OK will do, thanks

Just downloaded the workshop manual from https://www.expeditionforum.com/threads/ford-expedition-shop-service-manual.52273/post-507247

Going to do some light reading

 

[JohnT]

Some notes from the workshop manual

Non-Networked Illumination Operation
The BCM calculates the correct intensity for the dimmable non-networked illumination sources based on the ambient light intensity input from the light sensor and the requested illumination intensity level input from the dimmer switch (integral to the headlamp switch). The BCM provides a PWM voltage to all non-networked illumination sources.
The non-networked, non-dimmable switches are illuminated whenever the accessory delay relay is energized with the ignition switch ON or OFF

and also

Non-Dimmable Illumination
The non-dimmable illumination is on when the delayed accessory relay is active. The delayed accessory relay is active:
When the ignition is on.
For up to 10 minutes after the ignition is cycled from on to off and a front door is not opened.
Non-dimmable backlit switches are:
Door lock control switches
Window control switches

The delayed accessory relay (non-serviceable) is located in the BCM.