lately ive noticed that mud or sand, i engage 4hi and it works for about 8 secs then puff the fuse pops. so i disengage 4x4 put another one and puff again it pops it. sometimes i get lucky and it stays on for about 1 min or so but other than that its quick to pop.. anyone out there have any tips on how to find the problem and solve it?>

btw its a 94 Chevy Blazer Z71 and before this started to happen the 4x4 would work like a beauty. so yall plz share anything that could help me out PLZ!!

 

It is very likely that it is the actuator for the front axle. They are kind of in a vunerable spot and can get cracked allowing water in, shorting out the electronics.

 

is that the plug that is ( i think) on top of the t-case? because i know a while back i just wrapped it around in black tape....

 

The front axle actuator is on the front axle itself. It is located to the passenger side of the differential 'pumpkin'. The original actuator in your truck is an electro-magnet. GM has since revised the design and has a kit that will upgrade it to the stepper motor version which doesn't draw anywhere near the current.

Here's a quote found using "magnet+stepper+motor+actuator" as a search query:
And the link below will walk you through the install:
GM Fullsize Truck 4x4 Actuator Upgrade - GetDieselPower.com

 

wow u know wat ur talking about! lol thanks for the info ima end up doing the upgrade soon it should work and i read through it and it answered all my Q's thanks !!