Four wheel drive not working

My chevrollette 1990 4x4 1500 truck will not go into 4 wheel drive at all.

Always check your actuator, I replace so many of those on trucks just ;ile yours, that is usely the common problem. Just take the actuator out and keep the wires attached and then put the truck in to 4x4 and if it extends then it is working properly.

I see there is a 4WD fuse also.

I have a 1990 C-1500 Silverado with a 5.7 L V-8. Recently I discovered that my 4WD doesn't engage. I can't pinpoint exactly when it stopped working, but it will shift to 4WD but it won't engage. The light doesn't come on and when I check by spinning my tires on a loose gravel and dirt road, only the back tires spin. I'd like to fix it myself. Any ideas? Thanks!

Manual. Sorry I didn't specify.

The 4wd was working until the other day I checked the fuse and it was blowed. So I put another fuse in it and it blew too. So I checked under the truck to see if the wires were touching maybe shorting out but they looked good as far as I could trace them and help would be appreciated thanks

No the fuse didnt blow after disconnecting the wires

The front axles are not engaging in 4x4. The transfer case is, but nothing up front> the front driveshaft spins, but not engaging the front halfshafts. I have voltage to the actuater, and it is working. Therefore the fuse is fine, the 4x4 switch on the top of the transfer case is working(because of the voltage at the actuater, I know it is a complete circuit). There is no noise coming from the front diff that would indicate a brocken gear or anything. Also, the 4x4 indicator on the floorboard that should light up when the transfer case is engaged does'nt lite up. Im stumped, I have power where I should in order for the 4x4 to work but it doesnt. Please help!

If you have power at the acuator and the front driveshaft is spinning that would lead me to beleive that the acuator is faulty, try removing the acuator and visually watching it move, if it doesnt replace it, if it does the slide collar inside the axle may have damaged or be stuck. Happy hunting

Transmission problem
1985 Chevy Silverado V8 Four Wheel Drive Automatic

I have an1985 chevy 1/2 ton 4 wheel drive.
After replacing the u-joints and ball joints the truck will not go into 4 wheel drive. It has the shifter on the floor and when you put it in 4 wheel hi or lo ther indicator light comes on but the front will not engage.
Ant suggestions Dan