need a ground???

[notchman90]

my digital anl fuse block is draining the optima. i have it inline with my alternator 4g wire. it is grounded to the firewall causing the digital volt reading to stay on always. is there a way i can connect the ground to a neg. that is only activated when the car is on? would the ignition coil be one?
thanks

 

[HISSIN50]

i would wire in a relay that sends ground through the N/O terminal when the key is on. when the car is off, the relay rests at the N/C terminal. one could use 12 volts or ground as a trigger for the relay (wire it so the common terminal is a ground, if desiring a ground output when the car is on).

 

[notchman90]

sweet.. good idea. thanks