Adding some dash lighting..I need some help

I bought some little LED lighting bars from the local parts store. I removed the dash and found the intrument lighting wire on the dash connector. I spliced it in and used the ground on the connector. I hooked everything back up and tested it. I turned the light swith on and they worked, very excited. So I buttoned everything up, mounted the lighting bars. The I started the car and turned the llights on and they weren't working. Very bummed out. But they work when the ignition is off, its only when I turn the key on and then they go off, but the instrument panel lights work fine.
Where did I go wrong..................????