I am thinking of getting LED strips and put them under the dash and seats of me 03 Max. Here is my issue I want the LED to come on whenever the dome light is on. However I also would like the LEDs to stay when the car is on but at a lower voltages so they're not as bright (5v or so). Does anyone know how this could be achieved?
These are the strips I am thinking of getting: http://www.v-leds.com/Strip-Lights-L...47105-1-3.html

 

to get the reduced effect you can rig up some variable resistance. When dome light is on, you get full operation, when doors closed, you get reduced CURRENT on the circuit due to the resistance, which dims your LEDs

 

I have a basic understanding of circuits. So I think I understand what you are saying. Any ideas on how I could do this as simple as possible?

 

rigging another dimmer switch in would be easiest I think...but it'd be manually controlled. If you want it to be automatic, it gets much harder.

 

automatic would be what I would want I think. any ideas or suggestion on how to do it?

 

Not really on the application side, but on the theoretical side you're going to need to splice in to the 12V power, ground, AND monitor the line going to the dome light (and door courtesy lights as well)...The new dimmer switch is on the 12v side, and gets input from the dome signal (let's call it that). When the dome signal is on, dome light is on, so the LEDs will be on full as well.

When the dome light is OFF the LEDs need to dim...so the dimmer imput has to be able to register the change in the dome signal and adjust the circuit's resistance accordingly.

But you don't want the main 12V to be the constant, you're going to want to tie into one of the 12V wires that is controlled by the ACC switch, so when the car is off the thing won't drain your battery.

Sounds like you need to get down and dirty with some wiring diagrams, my friend.