Could be a few different things causing it not to come on start off with easy stuff first. Under hood fuse block has cool fan 1 and cool fan 2 fuses check them first. If they are good unplug fans make you a couple jumper wires ground black wire and one if the others (either one of the 2 that are...
Heater core lines go into fire wall close to your exhaust manifold more on driver side it’s little tricky to get back there but can be done really need u shape hard tube to put between lines so not to kink them and allow the water to flow well
ok so I have a 2010 cobalt with the 4 individual coils each have 4 wires to them 3 common on each and 1 different color on each from my research it appears that is my signal wire I have my autometer tach installed and signal wire hooked to that wire on one of the coils but my tach is nowhere...