Truck Won't Start No Sounds No Noises Nothing

[Gregski]

apologies for yet another truck won't start thread, hope you can walk me through troubleshooting this

1974 GMC 1500 1/2 ton V8 350 4 spd manual on the floor, brand new ProForm HEI dizzy installed months ago and working fine, not sure how old the starter is or the alternator

this is a daily driver (sort of) I drove it in to the garage couple days later it won't start

FYI I have a neutral / clutch pedal switch bypass on the purple wire under the dash that the previous owner put in and it's been there and working fine for years

PROBLEM - turn the key, the dummy BRAKE red light goes on the dash but the car makes absolutely no sound, no clicking no vrooming nothing, heater fan turns on and blows, wipers work, headlights work, horn does not but that's because it's broken

STEP 1 - Battery (well mine wise 3 years old and the wrong group size so I raplaced it with a brand new one, brought it home fully charged) truck still won't start with the new battery same issue

STEP 2 - Fuses, all look good

STEP 3 - ? Starter? I don't think I have power going to the purple wire that goes to the starter, I put a test light on it and had my son turn the key and the light does not turn on

How can I bypass the ignition switch in the steering column and just jump start the thing from the bulk head connector?