Hi i have a 94 gmc k1500 4x4. i went to put it in to 4 wheel drive and he light did not come on on the floor and i was not in 4x4. so i saw that the fuse was blown so i put a new one in and i went to turn the key on and it blew right away again. i then unpluged the tla switch it still did it then i unpluged the ball switch put a new fuse in then the same thing as soon as i turn the key.. what do i do please help me?

Bad actuator or wiring short I think.

I would think so..

Raise the truck with all 4 wheels off the ground, use jack stands for safety, Start the truck, engage 4hi/4lo operations , put in drive, take foot off the brake and see if the front drive shaft is turning the front diff.

it may be the sensor if it has one or it may be the unit it self

Go under the vehicle and check the four wheel drive linkage.

just shift to 4x4 on the fly as long as you are not going faster than 80 kms an hour.
four wheel drive low gear you will need to stop and put it in neutral, keep the brake to the floor and shift.

Make sure you have it in (N) before shifting it. Did it work before?

Hi:
All modern cars have a dual brake system, this way if you would happen to spring a leak in your rear brakes, your front brakes still work. When one system fails, you get a brake light. In your case, the first place to start your troubleshooting is to check the fluid level in the brake reservoir. If either the front or back of the reservoir is empty, you have a leak. If both are still full, the most likely problem is your master cylinder failing. If you think you have a leak, look at the inside edges of all 4 wheels, and look for signs of brake fluid .

i had the same issue change push button cluster