There is no other way that I know of. I have an rpm switch on my car and had to get one for it. I have a fairly good electronics background, we tried the crank trigger and took the dash apart looking for a tach signal...there is none on our new cars, the Ford tach signal generator converts a high voltage signal to something you can use...just spend the 50 bucks and get it over with....sorry for the bad news...I can give you the part number for it if you need it.