Question about my cpu fan again

hear is the deal, when i start my pc the fan runs, then i get cpu fan error and it stops(i can visually see when it stops), so i unplug the cpu fan and try again, still get cpu fan error but the fan keeps working (so i can boot my pc fully and use it, untill i restart it). idk what the problem is, to me it just sounds like a poor connections but would like someone else's opinions (btw i just got new mobo and cpu for my computer so they should be fine.) i have never used the stock cpu cooler and heatsink as when i got the mobo i right away installed my after market cpu cooler, i cant tell you if this was a issue with my old mobo because it was not compatible so i had to wait to get a new mobo to use it. the cooler is the alpine 64 pro, the fan is 4 pin. Im running Asus M5A78L-M USB3 with the amd fx-4100 3.6GHz. any help would be nice, thanks in advance