Stuck in 4hi
 

Ok so for last couple of weeks I've been having to make a 250km trip from Niagara Falls to Lindsay Ontario. Normally I drive in 2hi as the highways to and from are clear, and the roads in Niagara are usually clear. The roads around Lindsay aren't though so I put it in 4hi as I always seem to get there after a storm and before the roads are cleared.

Coming back on Friday I noticed that I had driven almost the entire way back in 4hi, now I was fairly sure I had turned it off hours before, so I hit the 2hi and nothing, tried to go to 4lo in a parking lot again nothing. The lights flicker for a second when I hit the button but the 4hi stays solid. I wouldn't mind the fact that I'm in 4hi except that getting into and out of parking spaces feels like I have to fight the front end to go where I want at the low speed.

The blazer is a 98 four door with the 4liter, I have the 2hi/4hi/4lo buttons no tow mode button.

I hadn't experienced any problems prior to Friday, with one exception the week prior one of the times I engaged the 4hi there was a much louder then normal "thunk" when it engaged.

Any ideas?

It's not good to drive around in 4x4 on a non slick surface. There's no differential between the front and rear axle, so the back and front tires are trying to all spin at the same speed. Anyways, I can probably get you out of 4 wheel drive. You need to remove the battery and battery shelf. Under it is a servo with a vacuum line going to it. Remove the vacuum line (a rubber hose) and plug it with something (only if theres vacuum in it). That's the only advice I can offer right now. As for 4lo, are you putting it in neutral before trying to push the button?

Yeah, 4lo is from neutral.

Good thing the roads around here have been crap all weekend then, thanks though, I'll give that a shot tonight when I have an extra pair of hands.

Don't expect the light to change with this fix. All it will do is, hopefully, unlock the front wheels from the front axle. The light is remaining on 4hi because 1, the front axle is not disengaging, and 2, because when you're trying to go to 4lo, the transmission is not shifting into the correct range. I actually just solved my own 4x4 issue (vacuum leak). Yours on the other hands sounds like an electrical issue. Try checking the fuse labeled "ATC" which is present in the fuse box located under the hood. Pull it, check to make sure it isn't blown, and if it isn't leave it out for a minute or two before replacing it.