key pad programimg

i lost my old key pad i now have a used 1 how do i programing it 2 my 99cobra

Turn the ignition from off to on 8 times ending in on (not start) within 10 seconds if done right the doors will lock and unlock. Press any button on remote and the doors will lock and unlock to confirm programming. turn ignition off.

i lost my old key pad i now have a used 1 how do i programing it 2 my 99cobra