ScrapMaker

When I accelerate, not only does the compressor shut off (if I push the gas hard,) but one of two things is happening as well:

1. When I accelerate, my HVAC moves the vents to the defrost mode, for some reason.

or

2. The fan actually completely cuts off when I accelerate.

is it possible that when I accelerate for the internal routes to change? I mean, when you accelerate, doesn't the car lose vacuum? if the HVAC loses vacuum does it revert to defrost? maybe the vacuum of the car is holding the vents at the 'A/C' location, and when I accelerate, there isn't enough pressure to do hold it anymore?

or does the blower fan actually turn off or slow down somehow? this also makes me wonder how the only difference between 'Max' and 'Norm' is the air comes out harder... meaning there is obviously some way of the car to control the blower speed, regarless of the actual **** setting, (via resistance or what I don't know.)

one other symptom I have is I CANNOT make just 'vent' work. When I put it on that setting, it just blows out the defrost vents. 'Mixed' mode doesn't engage either, and if I have the switch at 'Vent,' it causes my windshield to fog up sometimes depending on the temperature, as it's warm air.

Does this sound like an overall vacuum leak problem, or a centralized HVAC problem? I know for certain I have an overal vacuum leak near the 'orb' and I'm not sure how bad it is really, but this whole HVAC thing is pretty recent.

Maybe the external vacuum leak just go worse and there's not enough suction to do what it needs to do in the HVAC system?

Hopefully I can fix this easily, because those damned vacuum hoses are a real pain... almost enough to make me wanna ditch the car...

thanks,

Steven

MrDude_1

theres a one way valve leading to the HVAC air doors.

this valve lets air out to the motor, but not back in.


normally, the engine (when not at WOT) sucks the air out of the HVAC air door lines, giving the vacuum needed to open the air doors.

the doors then stay because the one way valve does not allow air back in.


if you have no one way valve, the air comes in at WOT and the doors close to default (defrost mode).

if you have a slow leak, the engine can keep the doors open when running, but when the engine stops pulling a vacuum, the doors close.




you either have a hole in one of the air lines. a worn out selector ****(that leaks air) or a broken one way valve.

ScrapMaker

so a vacuum leak at the 'orb' in the engine bay should not cause the 'doors' to close back to defrost mode, due to this one-way valve?

I kinda wish it was just a vacuum hose in the engine bay, so I could just replace it, because the HVAC seems really complicated.

Do you happen to know where exactly the one-way valve would be?

I think it is some kind of leak, because before now, it just took a while for the 'doors' to move... like I would turn on the A/C and it would take about 3 seconds for the 'doors' to move enough to let in the air. Now it only works on MAX NORM HEAT DEFROST...

any reason you can think that I can go to A/C but not VENT?