So i pulled my dash to repair a leaky heater core.
 

It was just the hose leading to the core. so i replaced them, both of em. new clamps all that. Put everything together again. lol now my heater does not work. the new connector leaks somewhere so i have to pull my dash off again. PLUS check engine light no longer works....LOL anyone know which connector is the check engine light? I want to verify ive got it seated correctly.

Thanks!

There is a pigtail that goes from the back of the gauge cluster (with multiple plugs) to the main harness by the fuse block in the passenger foot well. Easiest to remove the panel around the fuse block (around - not just the fuse block cover) and check to see if the pigtail is plugged back in there.

The 280zx doesn't have a "Check Engine" light... I imagine you mean the CHECK box at the bottom middle that checks the body sensors like brake lights, head lights, washer fluid, etc ?