i'm not a 'guru' but i've had the same thing for about 15 years. double check your wires and the fuse. there is also a trouble shoot page on MSD's web site. these boxes, once they are working are fairly trouble-free. do have have a ballast resistor in line? if so, bypass it as it's not necessary. here's a link - http://www.msdignition.com/troubleshooting.aspx