I've been tracing the wires in my C100 plug, and I've been preparing a C100 to connect with a Speartech harness. I understand that thick red wires (A4 and G5) provide 12V power from the battery to the fuse box and beyond. The thick pink wire is powered from those red wires. What is the pink wire used for? One thread said that the pink wire isn't normally used for LS swaps.

 

The 12 gauge PINK wire is the old ignition coil power supply (pin F4). You can use it for switched power if you want. Be aware it is not fused at the fuse panel, but instead is connected to the main 12V power supply through the key switch. If something on that large Pink wire shorts then it is going to blow one of the main fusible links and take down a lot of stuff in the car.

 

I understand now. Thank you

 

I use that for my Ignition source for all of my swaps. Not only is it ignition, it's also giving voltage while cranking.

Jay

 

Ya, I used it too. It switches the relay that powers up my underhood power center.