blower motor keeps blowing fuses

[melocochevy84]

so i finally got the blower motor to work in my 81 c10 after tracing wires for a day and all is well except it keeps blowing fuses on hi . med and low work fine no problems u switch to hi and pop goes the fuse any ideas solving this problem thanks in advance

[ccz145a]

Make sure the ground is good.

[78 Chevyrado]

unplug the wire to the motor.  Then replace the fuse, and try all settings on the switch.

If the fuse doesn't pop, the fan motor is bad. If the fuse pops, its the relay or wiring

If the fuse pops with the motor unhooked, leave the motor unhooked, and unplug the relay.  then replace the fuse and try again

if the fuse pops at this point  with the relay and the motor unhooked, there's a wiring problem.  probably a short where a wire chafed and shorted out to ground.  Since the fuse doesnt pop on every switch setting, the problem should be between the switch itself, and the wiring out to the relay and motor.