what voltage should i read

[DOHCD15]

i am replacing my tach with a spiffy autometer pro comp, i have already drilled in the face to install the led turn signal lights. as a last checkup of power with me and my handy dandy multimeter i realized that i didn't read any more than 100mv of power from the lamps even with the turn signal on and clicking away. is there some trick to this because my multimeter should have at least seen 10-12 vdc? do the turn signal lamps have to be grounded together or somethin?

[Curtis240Z]

The OEM lamp socket needs to be grounded. The OEM tach case is grounded. If you look closely you will notice a small copper finger that touches the tach case when you clip in the lamp socket. I have experienced the copper finger breaking off so the circuit won't complete.

[DOHCD15]

thanks, my tach now works