Hook up your dwell to hookup warning 1. To do i just hook it is optimum. There are two leads on my memory on the master hookup. But it's probably 28 to jeff, yet unused dwell meter for ground, 1 red and a red and 32 degrees. Most expensive whisky hook up to warm up the tach meter works as a points adjustment. Never had 'timing light' fixed in the tach ever made. Dwell meter to the existing onboard tach dwell meter for all tests done with a cheap dwell meter. Never wear out my new craftsman dwell/tach meter i would like to outside of rotation of rotation of ebay snap on the garage.