93 4runner 4wd won't engage
 

I'm looking to buy a 93 4runner from the original owner, he bought it brand new, is an older guy and not too familiar with maintenance so he doesn't really know what the issue is. The front right outer cv boot is torn. Anyways, when you put it into 4wd, nothing happens, no light, and it remains in 2wd. The manual shifter goes into 4hi and 4lo as it should, but nothing happens. He says it hasn't worked for 2 years and he's driven it as a 2wd vehicle. Any ideas?? I'm out of town for two weeks for work and don't want to let this one get away but i'm not home to look at it myself