I thought all the guages in the M715 were electrical. Hence being Mil Standard?The only gauge that will work after converting your electrical system to 12 VDC will be your oil pressure gauge as it is a mechanical gauge.
I know my 715 was in fact I took the gagues out of my m151 and used them in the 715 for testing so that I could figure out which ones were good and or bad. Did I miss something along the way?