Ok on my 97 chevy dually 6.5 I found on the fuse for the 4x4 is blown so I put a new one in amd it worked for a few minutes then blew that fuse too so I put yet another one in and as soon as I locked it in that fuse blew also so my question is why am I blowing fuses like that for the 4wd?

 

Probably the electric actruator on the frt diff is bad or wiring to it is bad?

 

Well I don't think the actuator is bad because it still locks in and I can move the truck to make sure it is but almost instantly the fuse blows

 

Still need to check it and it's related wiring-fuses only blow from excess current draw or short circuits.

Have changed a lot of those actuators over the years.