Hi,
Seeking some assistance with folks with some electrical experience. Tried researching on Google but some of the key words is pulling up info i am not looking for.

OBJECTIVE: Adding additional lighting (low power ambient lighting) tapping into the triggered ground switch so that new lighting turns on/off (along with fade) based on doors opening and parking lights, just like the footwell lighting.

INFO: So the footwell lighting used a ground trigger. This light source turns on when the car is unlocked, is running full brightness when the car is running, dims down when the car is taken out of park.

QUESTIONS:
1. Anybody know how much amperage is pulled from a ground in relation to the positive wire? This isn't the case but for example sake, lets say 50W strip @ 12v is roughly 4 amps. Say you have the proper gauge wire for the positive going to the strip but a very thin gauge wire for the ground, what happens then? would it still break the fuse that's on the positive wire?

2. Relay question: in this case, the relay would be triggered by the ground wire to provide a stronger fading ground source for additional lighting. Are relays sensitive enough to utilize the fade function?

Hope that made sense, my verbiage isn't perfect but if someone hopefully has some insight.

Also open to suggestions for other sources/ideas. Thank you.