Just got this peice and the blinker won't blink and the tail lights won't turn on. Bulbs are good and the switch is good. What else can i do. Its an 89 metro .

Check the fuses. If they're good, check and see if everything in the back is properly grounded. If you have doubts, cut the ground wire from the tail lights, and make your own direct ground to the frame.

If I see a tail light out I use a test meter on the bulb socket to see if I'm getting juice that far. Usually I am.
My metro often gets corrosion in the bulb sockets. I get them going again by spraying and working the spring until it frees up . I also use a battery clamp brush to scrub them out. Patience and elbow grease.