Hey Guys, My Trucks HVAC system works but the vents do not blow air at the dash. I have found a broken hard plastic line located against the firewall that does have vacuum from it coming off the back of the plenum. I am hoping that there is a relation here. There are two hoses from this line with check valves at the plenum that I "Think" are for the cruise control and for the HVAC control assembly. I have checked for vacuum at the black hose going into the control unit, but can't get any. What I can't seem to find is where the other end of this line goes into the dash for what I believe to be for the control assembly. Any ideas?

 

There are 3 small plastic vac hoses that come together on the passenger side of the firewall witch control the vents and cruse I'll try to put a picture on here for you of configuration

 

There are some pics of the vacuum lines that you need to look at located at the bottom of page 1 of this thread: https://dodgeforum.com/forum/2nd-gen...cuum-leak.html

It's the bottom picture.

 

Well, with the pic that GreenGiant sent, I am thinking my next place to look for the other end of that broken line would be at the vacuum reservior. It must have just got hard from old age and heat making it brake off. I will take a look and post back, Thanks guys.

 

In the center of this pic is the broken vac line. What I need to know is just where it should go to. I think the vacuum reservoir is on the other side of the firewall inside the cab and there is a line already going to it. This broken line might be for the HVAC control unit. There is a check valve on it also.

 

It's hard to tell from the picture where the line is broken. There should be a line going to your passenger side firewall. Is that in tact?

 

Yeah, That one that goes into the top of the firewall that I believe is going into the vacuum reservoir in the cab side. The one next to it is broke off and I just can't figure out where it came from. There are a couple of more vac lines coming off this main line from the back of the plenum and they run along the valve cover to the front. I believe one of these vac lines is for the cruise control which seems to work O.K.

 

Ok.I'll have to look on my truck and try to get some pictures for you and figure out where these lines go. I won't be home during daylight hours till Thursday though I might not be able to get back about this till then. I see that you have a V10 engine. It might be a bit different than how my V8 is set up.

 

Thats the vack hose on my truck that once broke hope it helps

 

Thanks for posting the picture. That's the exact thing I was going to post a picture of. I hope it helps him.