MSefi.com read only forum (Jan.15,2018)

I'm building the circuitry to configure the spare ports & have a few questions just to be on the safe side.

1. I've connected 2 of the spare output circuits to the left banded side of D9 to power them. Is it ok to add 2 more off this for a total of 4? Can the proto ground handle 4 of these? You can see in the picture that I bridged the positive side of the diode in the circuit to do this.

3. I inadvertently ran IAC1 & IAC2 to switch the 2 circuits I built. I know this isn't necessary, but will it cause any problems?

2. What is the purpose of the diode in this circuit? I posted the schematic I followed below.

Thanks!

The relay coil is an inductive device; just like the ignition coil, it builds up a (much smaller, obviously) magnetic field that collapses when switched off, generating a voltage spike. The diode is a freewheel diode, allowing that flyback pulse to dissipate harmlessly through the relay coil, rather than through your electronics.

Ok, I understand on the diode now.


Do you know if it's ok to power multiple output circuits off D9 in the fashion I've done?

You aren't truly powering them from that point - you're providing a path to bleed off flyback spikes, and yes, you can use several connections there.

Sweet, thanks to both of you!