Has anybody figured out how to get this done and actually have it work.
I know many of you out there would really like to use factory tach.
I might be able to come up with something if I knew what the factory tach was looking for in way of a signal.
I have access to many signal conditioners using tooth sensing inductive proximity hi speed switches.
Red lion Controls makes a rate indicator that uses the previous switch. Its digital and back lit but still dont want a useless gauge in my cluster.

 

Dakota digital makes an adapter that will work with it. I am currently collecting parts for the sr5 cluster swap on my truck.

 

I am also in the middle of this and plan on using the Dakato adapter. I already have the adapter and added a "w" wire to a GM alternator. I should be able to let test it out in a few weeks.

 

Did anybody solve this issue?
I have the Dakota box hooked up and blinking as it is getting signal from the alternator, but no movement at the tach.

 

For anyone else searching for this.
"Flash319" let me know that you need to use the "high voltage V8" output on the Dakota Digital box. This got me working and I was able to adjust it so idle seemed about right. It seems that it is reading fast in the upper rpm range, but I need to get an optical tach to verify this. I may have to calibrate a bit more as I think it is probably outputting double time since it is set for a v8 tach.