Just bought this truck last week 4x4 wont engage it blows the 25 amp fuse under the hood every time you try to engage it. It has the 3 button switch. After the fuse blows if you push 4hi you here the tccm clicking? Any way of checking the tccm.I have the unhooked frt axle plug & tcase plug at the same time and tried to engage 4hi the fuse dosent blow. Any ideas?

What fuse is it blowing?
Unplug one at a time to find out where it is shorted.