hey guys, i have a 98 4wd Expy w/ 4.6. the a/c and heat work fine but are only blowing through the defrost ducts.

according to what i have read and researched, its probably a vacuum issue. i am a newbie when it comes to engines and vehicles. so i really need some help. i need to see exactly which lines/hoses are the correct ones for me to be looking at.

thanks

 

The one that heads into the cab through the firewall.
Make sure its connected to the engine or vacuum distribution block which is connected to the engine.

 

I had the same issue, and found out that were the vac lines connect to the AC/heater controls in the dashboard, there was one that had a hole in it.