Ignition hot wiring

[mrollings53]

I'm getting ready to wire up everything for my engine rebuild. I've got an electronic ignition, electric fan, 3G alt, electric choke, and tach going in, and each one of them wants to connect to 12V ignition hot. I'm trying to figure out the most convenient and reliable way to connect all of these things to the same pin on the ignition switch. I figure I can use a common bus bar to connect each wire; with only one lead going to the ignition switch, but I am worried that the current draw will be too much for the switch. Or, I can use a relay with the bus bar so that the current demand can be correctly handled. What have you guys done, or think would work better? I really don't want this to be a hackjob of splices.


To thank you for your help, here's some engine porn.

[basketcase0302]

mrollings53 on Fri Sep 21, 2012 10:06 pm
I'm getting ready to wire up everything for my engine rebuild. I've got an electronic ignition, electric fan, 3G alt, electric choke, and tach going in, and each one of them wants to connect to 12V ignition hot. I'm trying to figure out the most convenient and reliable way to connect all of these things to the same pin on the ignition switch. I figure I can use a common bus bar to connect each wire; with only one lead going to the ignition switch, but I am worried that the current draw will be too much for the switch. Or, I can use a relay with the bus bar so that the current demand can be correctly handled. What have you guys done, or think would work better? I really don't want this to be a hackjob of splices.

There is no "easy" way to hook all these up "safely" onto the existing ignition circuit so that they would all come on when you turn the ignition switch IMO.

If I were doing this to my truck...I would add one relay for the electric fan, (I added two years ago when I had a two speed fan in my early Bronco using a single pole-double pole switch) with a new circuit breaker for the fan circuit. Then use the existing power coming from the ignition switch, (after the resistance wire has been replaced with a 14 gauge stranded wire) to run everything else, (and switch on the fan relay).
Here's a simple one line headlight relay diagram that's easy to follow that can be used for the fan circuit. You simply use one relay if you have a single speed relay:
http://www.fordification.com/forum/view ... =8&t=48178