Hvac question

[Greg5OH]

So before assembling the dash and all that in my truck I visuall chcked every connector an put some vaseline on the vacuum connections. Now I go to pull a vacuum on the main black hose that is nromally hooked up to the T block on firewall..I cant get any vacuum. Constantly leaking from somewhere. My default vent setting is to defrost. Also had to manually put the fresh/recirc door to recirc since the vac solenoid dont get no vacuum!.

I will assume that by trying to draw a vacuum on the main black hose (there is a white and black one that come thru with the blower fan electrical wiring) i should be able to pull a stable vacuum down yes?

 

[79jasper]

Should. Maybe a line broke/disconnected under the dash or a ruptured diaphragm.

Sent from my SAMSUNG-SM-G890A using Tapatalk

 

[chris142]

Ck that plastic line near the passenger side hood hinge

 

[Greg5OH]

is it black or white? White one goes to the blend door vac solenoid, its good.

 

[Clb]

Mine rotted out at the ac actuator under the hood pass side hinge.
Fwiw

 

[rhkcommander]

if the hose is old it can de-laminate - separating inside and blocking things up.

 

[Greg5OH]

it would be able to pull a vacuu then. But I am not able to build any vacuum. Need to go through all the connects and pull the dash ugh.

 

[junk]

I don't know if you have to pull the dash. Probably need to pull the radio, heater controls and glove box. I think that would give enough access to check all the vacuum fittings.

I had a red hose behind the radio on a door actuator that was unhooked. There is also a connection on the passenger side behind the glove box IIRC.

 

[rhkcommander]

it would be able to pull a vacuu then. But I am not able to build any vacuum. Need to go through all the connects and pull the dash ugh.

I must not have read everything when I posted, my apologies

 

[Greg5OH]

Seeing as I cnt fidn the time to take the dash off and check all my lines, is there a quick and dirty way I can manually set the blend doors to floor/defrost position?
Being on defrost is ok, but my feet are frozen!!

thanks

 

[OLDBULL8]

I think I'd hook a Vac Gauge to the manifold, then disconnect each line, when you register a Vac then that line you just took off is the culprit. Of course you have to block off the port for the line just removed.

1st of all, is the Vac pump actually pulling a Vac?

 

[Greg5OH]

Yes sir, i dont know how many inches but it works and the shutoff works as it should as well. plug the port with your finger and it shuts off.
backgroudn info: I am using the vacuum pump off a super duty which controls the hubs and I think HVAC, but not sure.
I am using a vacuum reservoir as well to help with higher demands.

Problem with plugging off one line at a time is to get to one of em I gotta pull the dash off i think? I dont recall exactly where they are. ONe is by the firewall inside the engine bay (white) this is the blend door-and has a band new actuator. ONe is right above the trans tunnel inside, and then there is 1 or 2 more ya?

 

[dansvan]

Get a friend that smokes to blow smoke in to the system. Will show up right away where the leak is. Or use a smoke machine.

 

[Greg5OH]

that is a good idea indeed. But in the meantime, how could I manually switch it to stay in the def/floor position?

 

[DaveBen]

Remove the vacuum form the heating/air conditioning system and it will default to the defrost position.

Dave