Just like the title says.
one week ago the car ran great, had no issues ither than not liking the cold and being ugly as sin. I put in my HVAC controls and carpet, and now the fuel pump will not prime unless jumped, and car will not start anymore. Continuity from main relay to fuel pump is showing 6.8 volts, and I have a constant solid CEL, car will not go into diagnostic mode.

 

for starters, continuity does not refer to voltage, it refers to resistance.

But to answer the question you didn't ask: it sounds like you damaged some wiring somewhere when you put your interior back together.