98 stuck in 4wd low after plug/wire/rotor replacement

What the F?!
I finished the plugs, wires, rotor, and cap.
I reconnected the negative battery cable, and started the vehicle up.
Ran fine. No skipping....sounded ok.
Shut it off, came out a half hour later, and backed out into the snowstorm we are having right now. Put the vehicle in 4wd low, and as I went to pull out of the driveway, I heard it click once or twice, and went to switch back into 2wd, and nothing happens. I can't get out of 4wd low. Light just stays on regardless of whether I select 4wd high, or 2wd.
When I got back to my house, I think I could smell something burnt.
What the hell happened? Any ideas for tomorrow morning when I have to go to work?
HELP!!!!

can someone help me out here? what are some causes/fixes for having the car locked in 4wd? please help

I unplugged the battery again, for about 10 minutes. Reconnected it, and kept hearing the click that you normally hear once when you hit the 4wheel buttons.
It was flashing on 4wheel High now, as opposed to low. I put it in gear and heard a mechanical sounding "RRRRRRRRRRRR" like a motor. I immediately put it back in park. I tried to switch to 2wheel drive, and it did it. Put it back in gear, and no more sound. I didnt dare put it back in 4wheel yet because I was afraid it'd get stuck again.
Anything that I could've done while changing the wires, plugs, cap, and rotor that could be causing problems here?
i.e. - an unplugged vacuum line that would cause this? an unplugged connector that would cause this? anything?
The only thing thats made a difference since this happened, was unplugging the battery....where as I said, I hear what sounds like a relay click and flashing of the 4wheel/2wheel buttons.
I can rule out the fuse considering the fact that I can still switch from 4wheel to 2 wheel. If it's the motor, its expensive right?
I'm dreading taking it to the dealer, as it's a $80 charge just to diagnose it...forget parts and labor to fix. I've learned over and over, it's always less to fix then they tell you. I'd appreciate any help possible.
thanks

I believe it just has 2wheel, 4wheel Low, and 4wheel High. Why?

There are people on here that know alot more about the 4wd setup than me (I've never had any problems other than it going in by itself about once a month), but I would suggest that you check the vacuum lines where you were fumbling around with the cap.

no service light whatsoever.
on startup, all lights now come on, and shut off a second after.
As of now, I can switch back and forthe ever since I unplugged the battery for a longer period of time this morning.
I would think whatever it was/is, is definately gonna happen again though.
I guess when I get a little cash ($80) I'll bring it to the dealer to have them check it then. Just seems like such a rip, especially when commonly they don't even correct the real problem. They just go for the most expensive part to replace.
If it happens again, I won't have a choice, I'll bring it right away. Any other ideas?
I did actually check for vacuum lines and connectors, but didnt find any that werent secured. Thats why I asked if there were any specific ones to check.

Considering the fact this showed up after changing the wires etc, I'd take a look at the vacuum hoses for the 4 wheel drive. Sounds like the elctrical side is working but not the vacuum. The burning smell, check and see if a vacuum line has been melted from the exhaust manifold.

I would be GREATLY appreciative if someone could snap a pic of the vacuum line that is responsible for the FWD. I'll owe you big time if so!