Hey guys, I have a 2002 Expedition XLT 4 wheel drive with the 5.4L. I've been struggling trying to figure out the vacuum lines. I thought if someone could explain their purpose and where they connect it would help me a lot. I don't know where they connect to the main vacuum source and I think there are different vacuum systems...right? One for the 4x4, one for the cabin ac, and then .....? Hell if I know. Whatever help anyone can provide would me most appreciated. Thanks

 

All that vacuum comes off the intake. You spring a hose leak, your 4WD will try to lock in and the AC vents will eventually “stick” in defrost mode.

Passenger side firewall is where those hoses run if I recall. The AC hose is a skinny one and it branches off and runs right into the firewall. I don’t recall where the 4WD vacuum runs to as my truck is 2WD and that vacuum hose port is just capped off.

I’m not near my F150 or I’d show pics. If you google up “2002 Expedition vacuum hoses”, something helpful should come up.

 

Thanks a lot for the help. Now that I know the source all comes from the intake I have a better idea of how to run them. I have a diagram for the 4 wheel drive and I got the one going into the cab for the vents and AC. I just didn't know where the source of the vacuum lines started. I really appreciate it a lot.