Continue to blow fuse 24, whis is the 4x4 fuse, when switch is in 4wheel drive it continues to flash. Mitchell ondemand's only TSB was a cold weather activation issue. which is not the problem in my case. I have traced all wires on transfer case and front diff. w/ no issues found. Could thispossibly be just a bad acuator on the front diff?

SOURCE: 1993 chevy 1500 4x4 pickup no power to front actuator

check all wire conections also replace the actuator on the front axle but check for power there first if you have power replace that switch as well .

SOURCE: I have a 94 chevy 1500 4x4 the 4 whell drive is

then t/case isn't good.

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.

SOURCE: 4wheel drive not engaging 1993 chevy k2500

had thesame problem on my1993 k1500. front axel would not ingauge. Ihve the independent suspension no th solid axel. my solution costed70 dollars and waste frontaxel actuato. this is on he passenger side ofthe frontaxel pig andmine hd a 2 wire round pin plug. some have a 4wire flat pin plug. it wasas simple as unplugging te old one and unscrewing it ad screwinh in the nw one and plugging itin. now hve fully functionl 4x4 aga. good luck.

Harvey N Tawatao

• 3854 Answers
• Posted on Dec 30, 2009

SOURCE: Front diff. wont lock into 4x4. Transfer case

The cable from the differential to the accumulator should move somewhat freely. If it does not, then the cable may be froze up. You can lubricate it with some penetrating oil and work it to free it back up. You may have to remove it to free it up properly.You may find the cable shield towards the bottom end is broke off and the cable may completely be froze up, it's common on the Blazers. You can try pulling on the rod that the cable clips into in the front diff to disengage the front axle. If you cannot get it to engage that way, then you will likely have to pull off the passenger side extension housing to access the engagement collar and fork. If you cannot get it to engage by pulling on the fork in the axle, then you will likely have to disassemble it.

You will likely have to file down the leading edge of the gears. They should be beveled on the sides of the spline to aid in engagement. Hopefully yours is not chipped like the one in the front of my old S10. Mine chipped the splines on the axle and split the collar from being partially engaged under power

The right axle and has splines at the end of it. The Output Shaft slides into the carrier and has large teeth on the other end. The collar it has large teeth inside it that mate with the Output Shaft with the Fork.

The collar rests on the axle, the fork wraps around the collar. Then you push the 4x4 button or shift your transfer case into 4x4 it starts spinning the front drive shaft, which spins the carrier and the short shaft. Now your in 4x4, BUT the front axle needs to lock the right axle with the carrier. A switch on the transfer case routes engine vacuum to a diaphragm under the battery tray, that diaphragm pulls a cable which pulls the collar and forces it over the short shaft. Now your front diff is locked. When you take it out of 4x4 the vacuum switch closes and a spring pushes the fork and collar off the shaft unlocking the front diff.

The problem with mine I think is that the large teeth on the Output Shaft and the inside of the collar are worn at the tips, not allowing them to join together, and the more I drove it around with it clicking, thinking it would lock eventually it just wore the tip of the teeth more.

If that is the problem, You should not have to mess with the differential case. You should be able to get the passenger axle extension tube off, but it may require popping a ball joint, then disconnecting the CV shaft from the axle extension tube, which would allow you to then pull the extension tube.

Good luck and hope it's just the shift cable retaining clip in the housing that broke.