My car battery dies when at cranking ? I was fixing fuel pump. Lights dim after I crank 2nd position ? Starts sometimes?

I am fixing my fuel pump, i turned the car on yesterday with the pump rewired as the module burned on the plastic where power wire sits on the inside of the module top connection. I cleaned it out and got it to power up again. So my car now won't start and battery dies when cranked but only at start position, I reconnect cables and battery is good until I crank it.

So could it be the pump being bad making this happen ? I had my bro start the car as I sat in the back to watch the module run for leaks ect to see what caused the power wire from the actual pump to melt at the connected on the inside top on the module (i diagnosing this and was fixing this befofe any battery issue). He started it and said it won't crank but lights stayed on and bright , he then left so I moved the module so I can try to start it and it started like he was lieing to me like no issue. Next day I go to start it and once at crank lights dim and power gone. I take off battery termials and put back on and light are back. I was thinking if I move the wires on the module it causes this, or the fuel line into the pump module was loose.

,how could the pump do this as I think it's the cause of messing with the power as it only happened after my pump died. I took it out and seen melted plastin in connected where red power wire sits. I cleaned it out and hooked it up but only wires and line and it ran. So I been testing it

Then this happened with battery

NO fuses blown/bad relays