Chevrolet Repair: S10 4x4 not enaging and idle is high, vacuum leaks, engauge

Question
I just bought an 89 S10 4x4 with a 5spd and 2.8. It idles at approx 1500 to 2000 rpm all the time, I can't here any obvious vacuum leaks. The 4x4 front axle lights up, but the indicator always shows 2wd, never 4wd, neutral or 4lo. The tcase seems to work, cause I have neutral and 2lo.

Answer
Hi Tim... i need a little more info. is this an electric 4x4 engage system or floor mounted shifter. first place to look for a vac leak on one of these is the vac pot for the 4x4 if it is vac engauge.if it is electric over vac engauge check the solonoids that open the vac to the pot