In all the questions about tuning with the cam change just noticed this problem. Its a 89 RS swapped 305 up to a 350. Fuses test good and everything looks like its hooked up. Doesn't blow now but did before engine swap. Blows on no speeds or temp settings.

 

are you actually getting 12 volts to the fan connector, take the connector loose at the fan there should be two wires, test the wires with a test light a voltmeter would be better, find out which is the power and which is the ground, plug test light to ground on battery and touch both terminals of the connector if it lights up that is the hot and it is good, hook the ground of the test light to the positive and touch it to the opposite in the connector and that is the ground if it lights up the ground is good, you must do this with the key on and the fan turned on, if you find you have good voltage then your fan is just toast.