When I turn on the defroster, defroster only - not heater or AC, the idle drops a few hundred RPM?? Vacuum leak I assuming but I don't know where to start??

well if u have ac it turns the compressor* on and if somethings wrong with ur engine maybe? I dunno it would lower ur rpms. On my ea81t u turn it on it drops like 50rpm then it goes back to normal when the computer tells it its got a bigger load... Maybe? i dunno...

Yes - when the defrost is turned on, the AC is automatically engaged. Your AC idle up system is not working properly. The throttle should be opened up when the AC comes on by this system.

 

GD

When you turn on the defrost, the A/c system comes on cause the A/c system collects the moisture on the evaporator, (this is why you see water coming from cars during the summer time). If your idle up solenoid isn't working right (vacume controlled diaghram near the carby) then it will drop down a bit. Check your other post, I think I got this one covered.

Thanks guys. I am new to Subarus. Can you tell?? I have had almost every amke of car now. I played with the vac hose and found the place I think it should be connected but now the idle will jump like 1500 RPM when I turn on the Defrost. And it doesn't do it all the time. I think I have a bad something or other!!