I'm wanting to take the Excursion interior light override modification a step further and was interested to see if anyone else has done similar or has diagrams and such.

I'd like to tie the interior lights into the photocell on my Excursion, since it's equipped with the automatic headlights. Reason being, if it's dusk/dark, I'd like for the interior lights to come on with the doors being opened. However, if it's day time, the lights are pointless anyways. You're probably thinking, too much work for the end result, but I've got several kiddos that try to help me make sure no interior lights are off, when in reality they are turning them on (accidentally). Also, with the large quantity of kiddos, sometimes I come home from work and a door isn't fully shut, causing lights to remain on.

[I know - Solution: Stop having kids.]

Just went through a large ordeal with the FICM due to battery and alternator issues, don't want to have to pay that price again. So I'm trying to determine every step possible to help in aiding that.

 

There are a couple of threads about how to add a switch to disable the interior lights. Assuming this is a +12V line for the lights then just cut the line and tie it into a wire run from the headlights. If it is some other voltage then put a relay that is controlled from the same headlight line. If unsure just do a relay.

If doing the relay check to make sure whether you need a current limiting resistor. Consider adding a switch to bypass the relay/headlight line in case you need the interior lights when the headlights are off. Also a good idea to add a fuse where you tie into the headlight power.