4 wheel drive

SOURCE: 1993 4X4 BLASER 4WHEEL DRIVE

Your blazer is equipped with a shift on the fly four wheel drive. That means that at speeds less than fifteen miles per hour you can shift into or out of four wheel drive by simply pushing the four wheel high button. If you wish to shift into four wheel low. Stop, put the transmission into park or neutral, and push the four wheel low button. Same procedure for shifting back out. Never shift into or out of four wheel low while moving. And be careful in four wheel low. At full throttle your still barely moving, you don't want to blow your engine up!

SOURCE: 4x4 wont engage

There is a switch that has twwo wires going to it, it's located just above the motor on your transfer case,on the drivers side, one plug goes to the motor and the other goes to this switch, it's the motor that shifts it into low and high range, I'm not sure what the switch is called but it tells the front end when to lock and unlock.
Hope it helps

SOURCE: 4 wheel drive will not engage (1995 S10 Blazer)

I had this same problem a few years ago. In my case I didn't use the 4 Wheel Drive very often and the tranfer would hang in 2 Wheel. I fixed mine by tapping on the transfer case with a hammer while my wife switched back and forth from 2 Wheel to 4 Wheel.

SOURCE: when i put my 03 chevy 4x4 in 4 wheel drive there

you may have a broken transfer box or a damaged locking hub on the wheels that arent used in 4x4 mode, i.e. if your car is FWD unless its in 4-low, check the rear locking hubs for failure. Other wise it sounds like a transmission fault in the aforementioned transfer box or differential.

Harvey N Tawatao

• 3854 Answers
• Posted on Dec 02, 2009

SOURCE: I drove my 1994 z71 truck through a creek and now 4x4 doesn't wrk

On the full size, the front actuator is electric, not vacuum.

When in 4wd mode, a switch on top of the transfer case conducts 12 volts out to the actuator. Wire #50 (brown) is the 12v feed, and it conducts to the light blue wire (#900) to the actuator.
When shifted out of 4wd, the switch opens up and no voltage goes to the actuator.

Check voltage at the connector for the front actuator (at the front differential - it looks like a large bullet that threads into the front diff.) If it has 12 volts, the actuator is the problem. If it does not have 12 volts, check the transfer case switch and the power feed to the transfer case.

I'll assume it is the actuator, if the plug to the actuator is getting 12 volts when in 4wd.
The way this actuator works, is it is a sealed chamber that gets heated by voltage. When it heats, the pin in the end swells and pushes a shift fork in the front differential. The shift fork engages a spline on the passenger side of the differential, and boom! you have 4WD.

GM offered an upgrade to this actuator that is a motor instead of a heated device. However, it requires a small harness addition, a spacer, and a new actuator. It is about a $150 to $200 option.

If I were you, I would buy a new heated actuator. They are available at most auto parts stores, and are about $90. They are also on eBay for about $55 plus shipping. These are very easy to change - just thread out the old one, and thread in a new one.

Good luck, That actuator is usually the problem 90% of time.