Wire step LED's to door switch

[Torqr]

Step lights needed in my 96 van, must work with door switch for overhead courtesy lights. I have the LED's in place with own ground, but only work when switch is open, so it's a grounding closure. Have tried every possibility including LED positive to ground only; should work as parallel units. Do I need a diode and/or relay? Would appreciate any straightforward explanation, thanks!