I was looking over my diagram and one of the hoses shows it goes to accessory. From another thread, it mentioned going to something that controls doors for heat/ac.

Does this need to be hooked up? Is it optional? Do you have a picture where it would be hooked up at?

Mine currently isn't hooked up and I'm wondering if it needs to be.

thanks

 

You need to hook it up if you want the accessories like AC, heater, and possibly some others, to work properly. Because the hose is hanging in the breeze, it may also be causing a minor vacuum leak affecting proper engine operation. You could start looking at the HVAC plenum where there are several vacuum operated motors controlling air doors.