'96 K2500 4WD Fuse is blowing

[Karl Stevens]

Hello, Newbie here. I have a '96 K2500 with 7.4 L.

The last two times I've used my 4WD, the 25 amp fuse has blown. In neither case am I certain the front wheels were engaged. The first time I was going up a hill and didn't want to spin the wheels, so I put it in 4 Hi. Then I put in in 4 Lo to come back down the hill. The second time I put it in 4 Lo to back a trailer uphill. So, I was never in a situation where it was obvious that the front wheels were engaged, but the transfer case obviously was, at least in 4 Lo. Interestingly, the 4WD indicator light on the push button never stopped blinking.

Also, I removed the fuse completely, but the transfer case still makes the 4WD clang when I pushed the buttons.

Any thoughts on this?

Karl

 

[Karl Stevens]

I read in another thread that a fuse could be blowing because the transfer case motor is bad and drawing too much power. Is there a way to test the motor to see if it's bad?

 

[Karl Stevens]

So, I think I have determined what is wrong with my 4WD. The front differential actuator is causing the fuse to blow. I disconnected the actuator and put it in 4WD, Hi and Lo. Push button lights blinked continuously, indicating the hubs were not locked in. The fuse remained intact. Then I connected the actuator and repeated the process. The 25 amp fuse blew in about 5 seconds, but hubs never engaged.

Any thoughts would be welcome.

 

[Karl Stevens]

I determined that my front differential actuator is causing the fuse to blow. I unplugged the actuator, and the fuse remained intact. Putting in 4 LO, the transfer case clanged in like it always does, so I know the transfer case motor is good and does not run off the same fuse as the actuator. I reconnected the actuator, and it blew the fuse in five seconds. So, when I have an extra $85, I'll replace the actuator.

The thing is, I believe the dealership replaced the actuator when I bought it used. They knew the actuator needed replacing, and had one on order, but I bought it before they could replace it. If they did in fact replace the actuator, I'm surprised it has failed already. I doubt I've used 4WD more than 40 times since I bought the beast.