Have some Lights, but not others, Help!

Yes I did find out some of the LED lights you can reverse polarity. The issue I have is every light on the car now works if the cluster is not attached to the car. As soon as I put it in the - and attach the 3 screws and it grounds all of the - lights go off. I am getting 8 V on the back metal housing of the cluster and I am figuring it is grounding outAnd making the circuit in complete when I put it in the car. It is baffling to me.