how can i wire up dual headlights to the factory wiring harness.....im just using cheap 90mm driving lights

 

luckily, RX-7's and almost every other type of car manufactured ever, come standard with dual headlights, so I'd say just find the stock plug.

 

tried using the stock harness got my power and ground but cant get them to work

 

Well, if you applied powe and gorund to the lights and they don't come on - they're broken.

The three wires on the plug for the headlight should have a ground (test pins for continuity to ground to find that) and the other two are low and high beam. Throw a DMM on it and hit the high beam switch to find which is which.

simple stuff...

 

Page 50-48 in the FSM, Red/Black=low beam, Red/White=high beam, Black=ground.