How long were you running the newly installed motor for? Right after you start, idle your car until it reaches normal operating temperature meanwhile bleeding out any excess air trapped in your engine. Once that is completed, if nothing is presumably wrong with your installation, the fan should come on. To verify if your fan motor works or not, directly inject 12v from your battery to the 2 pins on the fan motor side. If it do come on, then your problem lies somewhere on the harness side (e.g., fuse, or connection). It's really a simple procedure, but you have to do it a step at a time. Follow the top list and let us know how it went. Hope this helps...