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Discussion Starter #1
let me start by saying my new battery died, so I tried jumping it, to no luck. After I put a different battery in, I put the truck in 4HI, because I was in a snow drift...nothing, the fuse was blown, put a new one it, nothing, kept blowing fuses...not sure what it is unless its the 4wd acc.?
 

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Bayou Surface Drive, LLC
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Is the fuse the correct size? if its too small it will keep on blowing.
 

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Pat McCrotch
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Is the fuse the correct size? if its too small it will keep on blowing.
The also blow if they are green too...............:read:
 

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Discussion Starter #5
Is the fuse the correct size? if its too small it will keep on blowing.
yup, tried 2 25s, then ran out of them, had a 30 lying around for my electric fan, blew that one too.

I'm not sure how to described it any different, I'm far from a newbie, I have my own shop that I work on cars on my off days.

I put the truck in 4x4 and the fuse blows, the front hubs never engage. is the accualtor (sp) electric? or vaccum? I was thinking it was electric, its about 0* out right now, and the front brake lines froze and cracked, so I'll be driving to my shop once to fix everything. I just trying to figure out what all to look for so I don't come back with the same problem.
 

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yup, tried 2 25s, then ran out of them, had a 30 lying around for my electric fan, blew that one too.

I'm not sure how to described it any different, I'm far from a newbie, I have my own shop that I work on cars on my off days.

I put the truck in 4x4 and the fuse blows, the front hubs never engage. is the accualtor (sp) electric? or vaccum? I was thinking it was electric, its about 0* out right now, and the front brake lines froze and cracked, so I'll be driving to my shop once to fix everything. I just trying to figure out what all to look for so I don't come back with the same problem.
If you have a Haynes or similar type book, they show diagrams of whether your actuator is vacuum or electric. I am pretty sure vacuum is more common than electric, but I could have it backwards. Either way it doesn't sound like the actuator is your only problem to me. It could very well be fine, something is just wrong with the electronics/vacuum lines inbetween the 4x4 switch and the differential. My 97 blew the fuse once, I just pulled out another one from something I didn't need, and it never had a problem again. It blew when I was on a trail that only required 4x4 in certain areas, so I was going in and out of 4wd... then I randomly just lost it all together. Wish I could be more help....
 

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Pat McCrotch
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699 Posts
Ok I will stop fucking with you. Im not sure about the year of your truck but I know the newer ones are electric. Im not sure if the fuse has power all the time or only once the 4wd button is pressed. Ohm to ground the legs of the fuse because it should be inline to the actuator and other parts. You will have to find one circuit that is going to ground. Nobody is going to be able to tell you the exact cause. Its electrical you have to troubleshoot. Disconnect the front actuator if it does have an electric one which i believe it does. Then hit the 4wd button. No fuse blown you have your problem. If not then keep looking. Could even be a shorted pushbutton....
 

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How y'all durrren?!
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If you're talking about the truck in your sig, you're front actuator is the infamous GM thermal actuator. The thermal actuator uses the current from the truck to heat up a gas expansion chamber which pushes the piston to engage the front lock collar. These things are notorious for not working or suddenly disengaging in very cold weather, as the gas will recondense and retract the piston. I believe GM went to the straight electric actuator in '96 or '97, but you can upgrade to that with a little wiring work. I hope that's your problem, as it's not a very severe one. Try disconnecting the actuator and replacing the fuse, then test the 4wd. If the fuse pops, you have a short somewhere else in the system. If it doesn't, than you can start checking the wiring between the actuator and the truck, as well as narrow your suspicion to the actuator. If it does turn out to be the actuator, may I suggest the Posi-Lok. I don't have one for my truck, but only because they claim their system won't work with the NBS's (which I still don't see why not, but I don't feel like being the guinea pig ;) ).

Tom
 

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Discussion Starter #9
thanks guys
 

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bitter southern gun owner
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hey if you have 4x4 on the floor u still have a fuse for it correct?

that could be a reason that ur 4x4 wouldnt engage when the 4x4 vacum actuator is functioning and your rod on ur transfer case engages but nothing out it

i ran into a probilems so just curious
 
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