good morning everyone

im currently working on a 2005 monte carlo ss tony stewart edition
for a friend of mine
there was a toggle switch hooked up from the positive side post on the fuse box
to the radiator fans
upon hooking the wires back up to the oem wires and tried starting the car u get nothing no fuel pump no engine crank and or turn over
it started up fine when the toggle switch was hooked up but not understanding why when the wires was reconnect back to the oem wires and the car wont start
and yes i did make sure the wires was hooked up correctly
if anyone has any ideas it be most greatly appreciated