Whenever I turn the key on but not the blazer the 4wd button comes on but when I push the 4wd hi button the light doesn't come on please help!!!,

 

The 4wd button is supposed to light up when you turn your key on, but not start.
But we need more details, are you trying to engage 4wd while you have the truck off? or while its running?

 

Sometimes when I turn the key on the 4wd hi button will light up with the rest of the buttons and other times when I turn on the key just the 2 hi and 4 lo buttons will light up I'm not trying to engage it while its off. But if I do I can hear the transfer case make a noise like it when into 4wd

 

Well trying to engage when its off will not work, since there will be no vacuum, Have you checked your tccm fuse?
also, make sure you are getting proper vacuum, check under the battery tray for the vac assist and make sure nothing is unhooked, and check and clean connections on the transfer case.

 

No ur misunderstanding me the 4wd works. I'm 99% sure it's just the 4wd hi light doesn't work and I'm not sure why it does sometimes and sometimes it doesn't

 

Ooooooooooooooohhhhhhhhhhhhhhhhhhh gotcha, in that case, I would hit up a pull it yard, and get a switch out of one that is there, the switch might be going bad, or there could be a bad connection on the 4hi light.

I am not sure if the bulbs can be replaced or not on those, I know on the 4wd switch on my first gen, they can not be replaced.

 

It still does make me wonder if the 4wd works but I'm 15 and just replaced the motor in the blazer and It sits in the mud where it's parked so i put it in 2 floored it and it pull posi in the rear (g80). Then push 4wd. Floored it and it just moved so I think it works

 

well, a way to find out, is turn on the truck, push the 4wd button, get under the truck and try to spin the front drive shaft (from the t-case to the front diff) if you are unable to move it when you have 4wd engaged, then it should be engaged, unless you have a problem with the front diff.

but not being able to spin the front drive shaft by hand when 4wd is engage is a good sign

 

Ok thanks a lot