I'm in the final stages of converting my engine & ECM, only have a few more components to get wired up. I have two probably dumb general questions:

1) When doing auto wiring of components that require both a constant and switched (ignition) 12V power supply, do both of the power wires need to be fused or just the constant? For example, I'm wiring up a cooling fan and I know I need to fuse the main power line but does the line coming from the ignition need a fuse, too?

2) Is there a preferred location or method for tying into an ignition wire? I can easily get to the one that goes to the coil, but I'm not sure if it's okay to split that off into 2 or 3 for others that I need. I thought about using that wire to run to a small fuse block and then distribute the ignition power from there, but then I'd have fuses for them (which goes along with my question above). I know they make junction boxes or studs for either positive or negative from the battery, can one of those be used for ignition or does it cut the power down too much?

Thanks in advance.

 

 

Yes, sorry, that is correct - I'm not feeding the fan directly but rather a relay.

I was just wondering in general what the proper procedure is for tying 2 or 3 other devices - say, LED lights or something - into the ignition wire. If I tap into the ignition wire feeding the coil, is that going to negatively affect anything?