Curt, the tach light is best connected to the dash light power so it's lit as/when the dash lights are - the cig lighter could be powered from the same terminal as the gas gauge/ignition, so it will only be 'hot' when the key is on - or if it were connected to the same terminal as the ammeter it will be 'hot' all the time - your call, but however you do it make sure you have an inline fuse
Bill
