Fuses blowing when engaging fwd

[smoker 5]

When shifting into 4hi,(with floor shifter)fuse blows .No light on floor console either.
Installing new fuse,in 2h,do have power to actuator connector.
Question 1. Can the actuator be shorting out causing the fuse to blow?
Question 2. Can I run a direct 12v source to the actuator(while still installed) and hear if its` working?
Question 3. What is the other connection for?

1993 K2500 GMC with auto.tranny.
1st time posting here,sure hope you can help.

[Jeremy-WI]

What other connection? Is the front axle actuator made of plastic or metal(2 or 3 wires)?