greetings,

now that i have one problem solved, another has come up. this is more of a question. it would seem that i have my "air" coming out at the center vents as well as the lower vents while on "auto-a/c". the in-dash electronic climate control appears to be working fine and the air door "clip" is still in place below the blower control module and above the ecm.

i know that there is a controller somewhere under the drivers dash. however, before i ask anymore related questions, can that a/c controller be "reset" so-to-speak? by disconnecting the battery for a few minutes?...thanks!

 

As far as I know, the A/C duct work is designed to flow a tad to the floor - Page 1C1-5 in your Manual should describe it (if you haven't thrown it away!). Someone told me that the C4 got this design after numerous complaints that the console/footwells were being overheated by the exhaust sytem. I know the Manual is a bit confusing too, because the charts show no air flow from the heater vents when set to Auto 60, but the text outlines that this is the design of the duct work (And I know that mine has always worked that way). Now if you've got a torrent of air out of the heater vents, I'd see if there's any difference between the Auto and Bi-Level settings first (there should be). If not, you'll need to troubleshoot the Control Panel and Programmer and it might be easier to just check the vacuum harness to each of the three solenoids on the heater box first. No harm of course in removing power and clearing memory. Generally all that does is allow the Controls to redetermine how much time it takes to open and close the Temp Door and nothing will work while the door is being cycled (but that has nothing to do with air flow).

 

hey "sun" (respectfully), thanks for the reply.
yes, i caught my helms in mid air as it was heading for the garbage can! . if you (and i think you did) read a very long post of mine the other day, i had an unrelated problem (fuel related).

in doing so, i have touched nothing under the dash and only put on spark plug wires a few days ago so, nothing was disturbed.

i just got in and i am being rained on again so, the "battery re-set" will have to wait (not that it may make any difference other then screwing up my radio stations!).

maybe it's me and i am comparing the vette to my other car and that is why i poised the question. i reached my hand down while i was driving and it seemed that there was a little too much air at the floor and not enoug at center dash vents.

i have not verified the "quantity of diverted air flow from the floor to dash as of yet but, wil do so when the rain lets up (it's 95*+ here!). thanks again!

 

update.......
removed blower module and subbed out with known good one and no change.......

disconnected battery and no apparent change...........

it seem like there is more "air" blowing on the floor then through the dash vents..............

climate control will divert from vents to floor to windshield, but, when it comes down to bi-level, there appears to be little difference in the amount of air that is from dash and floor.......

heater box air door/clip verified and is ok.......

*there is an orange vacuum line that connects to the "vacuum motor/actuator at the far right passenger kick panel that i am unsure as to when it comes into play. i have applied external vacuum to that "motor" and it functions otherwise, i am unsure if it is getting vacuum through the orange vac line or where the vac line goes to as it disappears behind center dash.....

 

Orange is outside air and hooks up to another solenoid over on the passenger side kickpanel. It closes off the windshield inlet at 60-65. There should be a vent in the connection so that it won't flop around during borderline conditions.

Use the air flow chapter (8A-68-7) in your manual to troubleshoot the solenoids on the heater box - left side near the Programmer. Basically, you want to start by making sure all the lines - usually red and tan (Defrost), pink (Heat) and blue (Vents) - are intact. You should then be able to use a handheld vacuum pump to shut each HVAC door and then you can see what the air flow does. You can also see what has vacuum (and what doesn't) with each setting. There's a chart that outlines what they should be doing with each setting.

 

thanks for the reply!..question and i am a bit confused as some of the references are to the "front and rear" modes (8a-68-6)...i am lost with that statement. i have vacuum to the system as if i didn't, i could not get deflection to windshield, heater, center vents...

based on your narrative, it seems that i have to now dismantle the dash.

it is just that i seem to have a lot of air being diverted to the floor as if the system is "stuck" in bi level. i have set the temp to 60* on the climate control and that should get me inside air recirculated (no outside air) and a greater velocity as opposed to the outside air coming in...

i physically watched the air door in the a/c housing (engine compartment) close/open when i went from "hot to cold" so i know that isn't related. the orange vac line is getting vac and thats no problem as it and the "motor" is working.

it appears that it may either be a vac motor or a vac line to a motor that is at fault (maybe a stuck door?).

look at 8a-201-12 component location views, there is a vac plug fitting that apparently goes nowhere. i have that sticking out from the passenger side lower dash...what the heck is that for?..i have picts i can dig up to show if nessesary (this is an UNRELATED question).

 

Before you do anything drastic check that your vaccum valve at the intake manifold for the AC and Cruise Control systems is working properly. If it is broken, clogged, or otherwise not allowing a vaccum on the lines, the damper inside the air ducts will not open to allow air to pass throught to the AC ducts. The air will be directed to the winshield area and to the floor only.

I had the same problem this week and bought the correct valve and like magic my AC was blowin' again!!!

Check it out - I'm not sure if this is your problem , but might be.

Good Luck


Don Haller
Rockville, Maryland

 

thanks for the reply but, not apparently the problem...i have vacuum and it "switches" areas (zones) fine EXCEPT it seems that since i have more velocity and air flow at the bottom (floor) and not at center dash vents (although i do not know why since i didn't mess with anything), it would point to a stuck door?, a broken vac line?, or a leaking vac line to the bad vac actuator?. i hate to have to tear the dash apart!!

 

Well, if you're like me, you take off whatever it takes to make it easy -so I've had a good deal of the dash in the passenger seat, cargo area, garage floor etc - but (if you don't mind laying upside down in the driver's side footwell) you don't have to go that far.

Here's the drill: Rear is heat - Front is vents - Defrost is Defrost. Except for defrost, vacuum isn't being applied when a door is down or in Position A. GM, not wishing to waste the vacuum it's bleeding from the Plenum (and creating driveability issues), sucks the Defrost Door closed as a Default Position and with Defrost, it sucks it open, AND for A/C or Econ, all it has to do is keep it sucked closed. With A/C selected, both the A/C (front) and Heat (rear) doors are down and this keeps air (except what's built into the duct work) from flowing to the floor and what's getting churned by the Blower, comes out of the vents.

With Heat, vacuum is applied to the A/C (front) and Defrost and this shuts the path to the vents and you should only get Heat.

With Bi-Level, you have vacuum to Defrost and Heat (rear) and if you look at the drawing of the Plenum, you can see that some air still gets around the door so you get air out of the vents and the heater.

You want to find out if you're getting too much out of the heat side when you've selected a/c and since the door is normally closed (no vacuum applied), it's a little difficult to troubleshoot. Here's what I'd do: I'd see if there's vacuum to Heater (rear door) - just like there would be if you selected Bi-Level. If so, something is up with the Programmer or the signal from the Dash to the Programmer. If not, then something is up with the door - it may be stuck - but I'd bypass the solenoid and see what happens moving it around manually. I'd also try a handheld vacuum pump on the solenoid and see if you can get it moving a little better. If all that fails, you're going to have to take it all apart - But - before you undertake that, I'd certainly try to find another Vette and make sure there's a big enough difference to make it all worth it.

 

thanks again for the reply!..i can't see or reach a damn thing under my dash...i can't see how anyone could! so, it looks like i will start at center console and yank radio out (or should i remove the top dash cover?....

i have a spare climate control unit, do ya think i should sub that out first before i remove the dash?....i do have a vac pump but, from what i see, i still have to dismantle everything to get to anything to use the pump!..make sense?........

i am positive that the "floor" is getting way too much air velocity and it appearass that there is little to no difference from "auto air" to "bi-level"

 

I always start at the top and work down - as I said whatever makes it easy for me - but I would try that spare first.

 

a-ok............would anything i would need to get to, be visible AND accessible from the top if i have to remove the top dash cover? could a dirty or faulty climate control unit cause the problem i am having?......thank so much again!

 

Not by just removing the dash cover - main harness and duct work block quite a bit. The duct work can be removed and by now most of the factory seals (foam rubber) are probably long gone anyway. In fact, if you have a stream of air cooling off the ECM, that's a good sign that the seals are shot. The seals are no longer available (I don't think they ever were). I cut up some foam that came with a TV I bought and then wrapped it around the male side of the joint before inserting it back into the female side. Duct tape would probably work too, but it's difficult to wrap anything up once it's installed as the harness and a bunch of other stuff is in the way.

The solenoids are on the left side of the heater box, so to access them from the top, you'll need to remove the radio, then the control panel and removing the Display and the console might make it even easier. Been awhile since I've been in there, but I just keep keep taking out stuff until I get to what I want. If you do go this route, I'd replace all that's hard to get to when it's together - Flashers (4 Way and Turn) - Bose Relay if equipped, DIC bulbs to name a few. Check grounds too - 201 (if I remember correctly is the front harness ground) - over in the driver's footwell. The Electronic A/C Control Panel shares this grounding point but is a separate line with it's own lug. Clean up anything that looks questionable or solder on new lugs.

 

thanks for the reply.....it's 11:18pm here on the east coast and i am spent. i won't even hang around for an answer! at any rate, ok, so maybe i don't remove the dash cover, just the radio. my plan of attack will be to remove the center bezel, radio, and climate control and start from there, as to what i will be able to see, who knows?! i will however sub out the climate control to elliminate that as suspect.

i am still not sure what the hell i am doing or what i will be looking for, just probably an "doors" that may be hung up on a wire, a broken clip, loose, disconnected, or "worn" vac line.......i will probably wind up dropping the drivers hush panel to see what i can see. the programmer will be another issue as i haven't read up on that yet or how to troubleshoot, if possible.

 

.......started taking the dash apart this morn and through the center top dash vents i see an actuator arm that, whatever position i select on the climate control or temp, i have not seen it move.......what do ya make of this?.........gonna take dash cover off now........

 

darn it!....one of these days i am going to learn how to make the picts smaller!....

anyway, problem FIXED and found! it was a
pinhole leak in a vacuum line as in the picts below.

when i checked the valve and tugged on the line yesterday, all appeared secure but, when i rechecked today, found that it broke in my hand.

so, i dug out a piece of vac line (purple in color in pict) i had laying around and "spliced it in and all is well!........thank you everyone for your help!!!!!

 

Ha,Great find and fix!I had a problem on my former 86 and it turned out to be a broken vac line around the engine are to feed accessories.
Btw,I was about to suggest to jam some clean socks inside the bottom duct openings to see if that enhanced air flow into the fronts.

I actually did something like this on another GM car I had...the heater door cable broke off and there was no way to fix the bracket back on inside the dash so I stuffed a sock in there to keep it mix door shut and it kept the a/c blowing nice and cold without the hot flash symptoms of the door moving back and forth due to a cable.Not the same thing you had but plugging the lower blow vents with socks or small towels will force the air to go back up and out the front vents.

 

i hope they were clean socks!....