07 dodge cummins tach wire?

Alright i know this has been gone through a million times, but i can't find the info i want with a search. Is there a better, less invasive place to grab a tach signal from a cummins than at the ECM or the cam sensor? Done quite a few but i still hate hooking up there, just because i always worry about corrosion problems up here in Canada, plus it really isn't a fun place to splice a wire. Does anyone know where this wire comes from or goes to? There has a got to be a spot near the top of the engine or in the cab that is better. Think I might take the Fluke and start poking on the next cummins that rolls in here if i cant find anything else out. Tach signals from bypass modules don't seem to work up here, to much voltage drop from the grid heaters cycling after the engine starts, even when 12v wired direct to the battery. Anyone ever tried the 6 pin injector harness on the side of the valve cover? I wish i could have had the truck for an extra hour today to play around lol.

How did you ever make out with the tach??

I have a 07 that I want to do next week?

Matt