Which dome light wires do I tap into under the passenger a pillar to add foot well/under dash lights . There are 3 wires feeding the dome light does anyone know the color codes which is + and - and which is hot when the dome light is on ?
any help is always appreciated.
thanks
Dennis

 

I tapped into the trunk lighting circuit when I added foot-well lights.
CLICK

 

Coupe and roadster may have the same color code and wire configuration but the image below is from my limited coupe.




The dome light assembly has a single black snap connector with 4 of its 5 wire slots being used. Color code, polarity and purpose of the wires starting nearest the windshield glass are as follows:

You said you have 3 wires going to your dome light. Not sure how this will play out but if the roadsters color code are the same as the coupe, you will want to tap into the Red with Dark Green striped (RD/DG) wire or Brown with Yellow striped (BR/YL) wire for your footwell light +12V source, then tap into the Blue with Brown striped (BL/BR) wire as the ground. This pairing will allow your footwell lights to come on when either door is opened.

The Brown wire is ground for the map light function only so with the +12V source, the map light can be switched on or off while both doors are closed.
(...yes, I know. Nobody uses paper maps anymore.)

Otherwise, you can tap into the rear compartment light as another option.