Make sure your fan motor bearings are in good shape.
With the switch off, reach through front and spin the fan by hand (1 fan for SP1, 2 fans for SP2).
They should spin freely without any effort or noise.
If the fan doesn't spin freely, then it may be rubbing against the radiator(s), or the fan bearings are bad or going bad (esp. If they squeak).
An electric motor under load or stalled out draws more current. This can cause fuses to blow.
A short can blow fuses as well, so a visual check for chafed or damaged wires may be needed.
Remember, fuses for a reason.