DRFTSAINT

I have used the search function, and was unable to find an answer...

I have searched and cannot find the source of my problem...
I have an SR20DET swap in my HB 5spd, it ran amazing for almost 5 months now with no problems whatsoever... Then one night I start the car with no problems, turned my headlights on no problems, I started to drive away from my house and after about 500ft my headlights dimmed to nothing, none of my dash lights worked (no battery light, oil light, etc), and my radio shut off... My motor stayed running just fine, my windows, wipers, my turbo timer was still on, and seat belts all still worked, oh and my electric fan still worked... So I turned my car off checked the battery cables and as many wires as I could with my phone as a flashlight, and found nothing... So I got back in the car and tried to start it, when turned to the on position my dash indicator lights came on, but when I turned the key over I got nothing and my indicators went out comlpetely...

Things I've tried so far -
-New battery
-checked all fuses and bought new relay thats in the fender next to the
battery
-I tried bypassing the ASCD or clutch safety switch on the pedal
assembly
-I went back through the next day and checked all my wiring harness,
no cuts found
-I found my homeade harness for my fogs had grounded out against the firewall, but it had its own fuse and source to battery

Things that are irregular -
-I can hear my fuel pump kick on, but is very slow like it has minimal
power
-Headlights are extremely dim even with new battery

Things that I have thought could be wrong, but would like other opinions before I buy them, 1 Ignition switch 2 ECU dead (but engine light does light up when turned to the on position on the dash, which I thought had direct corelation to the ECU), those are my ideas, any help, advice, or opinions on the matter would be greatly appreciated...
If you need to know any of the modifications to my car other than that it has an SR20DET swap let me know...
Thank you