Can any one tell me why when I try and use the ac in my van that I get more air coming out the vents on normal ac than when I try max ac? Plus my ac worked fine last fall and now it seems to need a charge. But I can do that. Thanks.

 

It would seen one of your vacuum servos or motors isn't working properly. When "Max A/C" is selected the inlet port usually admitting outside air is closed, you go into a recirculating mode. Follow this schematic of the vacuum system for air flow direction


HTH

 

Thanks for the reply JWA. What you say makes sense. Can I assume that when the max ac is on, the place it draws air from to recirculate is on the passenger side somewhere below the dash? And I guess the door that closes is somewhere in the same general location?

 

Sorry for the late reply but yes you're correct. Look at the evaporator/core case at the lower right side you should see this:


Looking forward towards the engine bay just in front of that silver vacuum solenoid you'll see an opening which is the Max AC or fresh air door, Max AC command closes that door. (The solenoid shown in this view is NOT part of Normal or Max AC)

HTH

 

JWA....If I could ask a question.......
I am planning on installing one of those Ranger diverter valves to stop the hot coolant through the heater core when I turn my selector control **** to Max a/c and hopefully also Norm. a/c. I have looked at that illustration you have posted and am a little bit ashamed to admit I just can't make any sense out of it. So instead of you trying to explain it to me, Could you possibly direct me as to where I might look for a vacuum line that will operate this diverter valve when either in the Max or Normal a/c positions? The only thing I have found so far that is easy to get to is a removable cover (plate) right up on the top of the dash (well the top of the dash that goes up to the inside window & where the defrosters vents are. This gives access to at least one vacuum can that I could tee into BUT I am not sure that it's going to be the one I want to use because I don't think it is operating when I go to the a/c positions. In all honesty, I forgot just what dash control I moved to get it to operate. And there is no way to see just where the control arm it is moving is going to or what it is doing. It might just be opening or closing air flow to the defroster vents. (I say that only because it's located right up there near that area).
Is there a line I should be looking for under the hood that possibly is tucked up next to the upper firewall? That would seem to be the easiest place to tap into if there was something out there. Would hate to have to pull the dash off to gain access to lines that might be right behind the dash control *****. You probably know it's a PITA to pull the dash off of these things. Any direction is appreciated. Tom

 

I've experimented with bypassing the front heater core with maybe 3-4 DIY designed/installed systems in order to achieve what's generically called the "cold air mod"--the idea being to do exactly as you're planning. FWIW a well running and properly serviced factory A/C should provide you with about 38-40* leaving air temperatures at the dash vents in Normal setting.

My testing after installing all these contraptions showed nearly zero reduction in air temps as measured inside the van and compared with incoming ambient air intake point just under the cowl. I know more than a few have said they've seen significant temperature differences so take that for what its worth.

Following the above vacuum routing diagram you need only find the blue line which has vacuum present when A/C or Max A/C is selected. Those are best found and tapped into under that removable dash cover up top. I've used various types of tubing to do something similar have found the silicone stuff best but any snug fitting flexible rubber tubing should work just fine.

BTW I've added you to my Contacts List so you're welcome to PM me if I can be of further or more timely help.

 

Thank you very much JWA. I am now going to have to balance out the time/work involved with your reported findings.
I am not having any issues with the a/c at this time (that I am aware of), But then again I am not in Florida right now either.
Also I must consider that this is a Van & as I am sure you know.....Adding anything Extra under the hood is quite the task!
I also have read the reports of there being a significant increase (well, DROP) in temp. after doing this mod. That's pretty much
what got me to thinking of doing it. I guess one really has no idea of the condition of the air box / exchanger unless you open it up.
It was my impression that even if it was in good shape as you refer to that there was still a lot of heat on the heater core side of the box
and that caused losses to the cold air passing through the other side. (Sure , I imagine there is insulation on the wall in between but
there are so many guys that have done this & reported "ice cold at the vents now..."
GeeWizz, Now you got me all discombobulated! LOL. Thanks again and for adding me and the PM invitation. Tom

 

JWA, thanks for that. I was really busy at work and it took a while for me to get at it. It turns out that because I carry too much in my truck, that a plastic bag got caught up in the way and cut off a good bit of air. So that part is fixed. But I keep putting freon in and the ac gets cold, but after a few days it warms up again. I am thinking I must have a leak somewhere. I know there is freon with dye in it so I can look for the leak. I guess having it with stop leak in it is not available. Does any one place start to leak consistantly or is it hit and miss?