4 Wheel Drive/SUVs: 94 s10 blazer 4wd is stuck on, s10 blazer, cv axles

Question
ok i have a 94 s10 blazer and the 4wd comes on and off, it is electronic and the 4hi light is on, it seems to engage only when the egr valve acts up because the egr is bad, now it also mainly makes the noise and vibrations from the passenger side of the truck, it just had the driver side hub replaced and both front cv axles replaced about 3 months ago, i was curious if the switch on the transfer case was bad? or someone said pull the fuse so 4wd wont come on at all? can you tell me what fuse it is? thanks -nick

Answer
Nick,

The EGR valve should have nothing to do with your problem.  This valve is an exhaust gas recycling valve that has to do with your smog system.  The transfer case and drive system is completely separate from your smog control.

The noise and vibrations could be coming from your front axles, or the transfer case/transmission.  It is extremely hard on the drive train when you drive in 4-wheel drive on hard surfaces.

It sounds more like you have a bad ground, bad wiring or a faulty switch.  This needs to be taken care of asap, before something major breaks in the drive train.

I would purchase a repair manual for the Blazer at a local auto parts store.  They cost around $20 and are needed for most home repair or trouble shooting.  This manual will give you step by step instructions along with photos of the fuse locations, and information/trouble shooting the transfer case problem.

Carl