My truck is stuck in the defrost position. I have been reading about the vacuum system, but my truck has no colored hoses. They are all black.

I am unclear where to start. I have looked at the Vacuum diagram and have a chiltons manual, but it gives very little info on the system.

1. Always in defrost mode.
2. A/C wont engage.
3. All fuses are ok, nothing is blown.

Where in the world does the hose I am pointing at in the picture go?? And, what is the can that has this phantom hose?

I could really use some input.

Dave

 

hose you're pointing to is suppose to be open. It's the intake for the smog pump. The white vac hose in pass corner of the engine bay is usually the cause of hvac stuck on defrost. Check the white hose, it's in the pic behind your hand. Cut off the rotted section and slide some rubber vac hose on it.

http://fullsizebronco.com/forum/show...0&postcount=19

 

Turns out the black plastic vacuum reservoir is shot.

Apparently, my good ol 1996 4.9L Eddie Bauer F150 which I bought in Lawrence, KS came with a California Emissions package. It's says nothing about that anywhere on the truck. Also, the air vac reservoir for my truck (if you order the part from ford) isn't for a 4.9 liter engine... if your 96 4.9 has California emissions, you need the Vac Res for the 5.8 liter V8.