Guys

I can't seem to get any air through the dash vents. The blower is working and blows through the floor and windscreen (defrosher) vents. No matter what setting I have the vent lever (normal or bi-level, or any other), it never blows through the dash vents. I assume this is a mechanical control (what switches the air flow from floor/dash/defrosh vents)?

Any ideas what this might be??

thanks

Wilbo

 

I had a similar problem with my 96 dodge van found vaccum lines under hood to be dry rotted.

 

ah, that could make sense. I've been doing a lot of work in and around hood/firewall recently. Is there a specific hose/line I should look for? Should I look under hood or inside cab? I suspect I've dislodged something

Not sure if this is related but recently I've noticed the idle isn't steady and I know this can be related to vacuum??

many thanks

Wilbo

 

On the passenger side of the intake is where the HVAC vacuum line connects, along with it's one-way check valve. From there it runs to the vacuum reservoir behind the passenger headlight. Then from there it runs through the firewall to the dash controls.

 

thanks, found that one. So best way is to remove the lines and check for leaks/breaks? There is certainly a good 'pull' coming from the HVAC line engine point. I'm hoping a line has become disconnected rather than leaking. The check valve can give up as well ? Do you think it could be a flap problem where the air is mixed?

Wilbo

 

If you mean the hot/cold air mix (blend door) then no. It could however be the vacuum actuator that switches the airflow from floor to vent to defrost.

Did you try applying vacuum to the HVAC vacuum line from the side of the intake to see if it holds vacuum?

 

Yeah I mean the floor/vent/defrost flow. As I cycle through the buttons (normal/bi-level/heat/defrost) there is a change from defrost to floor as in the defrost setting has more flow to floor than when on the heat setting - not much but I can notice a difference. So 'something' is moving a bit.

All I've done so far is pull the line from the intake and stick my finger on the intake line which is sucking like crazy. I've visually checked the lines but not back to vacuum reservoir or from there back to dash. I'll check those lines next.

I've read about trying to notice a hissing when diagnosing these problems, which I think I can hear above the noise of the engine. I think I might have dislodged something when doing the plugs and wires...?

Do you mean testing the reservoir end of the line with the other plugged in normally?

many thanks!

 

Found it!

Looks like the thin black line from the T back into the dash got melted on something (probably close proximity to heater core lines).

My neighbour had some identical black vacuum line from his bike - product called Scottoiler if anyone can't any original.

thanks Alloro and Cgees

Wilbo

 

help no airflow

 

We're not mind readers, try explaining the problem better, what causes it, any steps you've taken to try and narrow down any of the components which could be bad. I could simply reply, "open your window" to what you've written.