Having trouble planning ignition sources for all the different accessories in my project car. I know you can use the two IGN spaces in the fuse block but I need more than just two. All of these items need an ignition source:

• aftermarket gauges
• cooling fans
• LS alternator pigtail
• Holley terminator ECU harness
• Holley terminator transmission harness

what is the best way to provide this many??

 

I left the stock fuse panel and chassis wiring in tact for those functions (my original wiring was in good condition). And added a stand-alone underhood power center for all the new engine functions (engine, ECM, fuel pump, fans, trans). The underhood power center gets power from battery and is switched on by the original distributor coil wire (C100 F4, Pink).

Aftermarket gauges can be powered by the same wires as the stock gauges. Cut off the stock dash connectors leaving about 6 inch of wire pigtail. You can crimp on terminals and add a connector to that pigtail if you ever want to go back to stock gauges. Likewise, add a connector to the remainder of harness in the car, and make yourself a new plug-in pigtail for new gauges.

If you need switched power for stand-alone backlighting dimmer **** (like Speedhut gauges), then you can tap that power from the fog lights buttons harness. See Post #652, https://www.thirdgen.org/forums/ltx-...ml#post6111293

I never did install my Speedhut gauges. Decided I better liked the look of the stock gauges.

 

Planning on doing exactly what qwktrip described, can even use one of the fuse panel ignition sources to switch it on. I like the idea of having one switched 12v source and one full time battery source to grab power from. the battery source prevents your battery from having 47 different wires hooked to the positive connection lol

 

How does this work? Could you please share a crude diagram showing how the pink wire switches on a power center that is connected to the battery. I would think a power center connected to the battery would have constant power.

 

I have something like this powered by a direct connection to the battery that is switched on and off by a relay. The relay is controlled by a 12V switched ignition source.

https://www.ebay.com/itm/31522897252...Bk9SR7rMn67OYw

 

My underhood power center includes a large relay that powers all the switched circuits for ECM, ignition coils, fuel injectors, etc. The C100 F4 wire is simply the +12V enablement to the field coil of that relay. The power center also has other smaller relays for fans, fuel pump, A/C compressor, etc, that are all controlled by the engine ECM. I did not build this power center, I purchased it pre-wired and tied each wire into my car.

My main power distribution begins with a 6 AWG cable that goes to a ring terminal post at a large fuse holder located close to battery. That ensures that only a small run of cable is unprotected. That fuse holder has 4 large fuses that power everything in the car, with the exception of engine ECM which is wired directly to battery B+ and B- posts. Downstream from the large fuse holder are the fuse panels (stock and underhood) with all the individual circuit fuses and relays. My memory is a little fuzzy, but I think those large fuses are: 1 for HVAC high-speed blower circuit; 1 for the underhood electrical center; and 2 that replace stock Fusible Links 'A' and 'B' (I cut out all the stock fusible links).

My fuel pump was a later add-on (afterthought) and I can't remember if it was wired to battery or into that main power distribution fuse block. I'd have to follow the wires in the car to trigger my memory. I did not wire it through my underhood power center because I was trying to minimize voltage drop in the circuit to fuel pump.

I was a first timer when I did the majority of this work, and much of it is patched together and doesn't look very good. If I knew what I know now then I could have done a whole lot better!

 

Here's the one I made using a 95 Camaro under hood fuse box for a "base" to build from. My car was an 84 Carb from the factory so it had no electrical for PCM, injectors, electric water pump, electric fuel pump, Fans, Fog Lights, etc...

 

to use relays and make a distribution block from 12V ignition you can do something like this

 

awesome - thanks for the explanations everyone!