the air cond works but only blows out defrost vents at idle then when engine get to 1600/1700 rpms air comes out dash vents. I know it is a vac leak or low vac i just dont know where to start looking. the cruise is working as it should.

 

The connector for the vacuum to the AC controls is right over the exhaust outlet from the turbo. If you have aftermarket turbo/exhaust installed I have seen it where that gets bumped and it falls against the pipe or near enough to melt. I would start there. The plumbing runs along the rubber strip of the hood seal on the fire wall. The connectors for the 4WD etc are just above the brake booster under the rubber lip. A cap can crack on any of the empty ports.

Hope that helps.

 

I had the same thing happen. Defrost is the default mode.

 

mines a 98 12v same thing happed i found the leak just to the (driverside) of the ppump next to the throtle linkage.lil dog is right you have to follow all the vacuum lines and ports to find. good luck

 

Same here.. The cheezy right angle rubber boot over the vacuum pump nipple had a hole on the underside and was sucking LOTS of air!
A new generic vacuum boot from Autozone fixed several things with my A/C and cruise control system.

ALso greatly reduced my "BlowBy" coming out of the oil filler!