LBZ HVAC help...

[OperaHawk]

It looks like I will have Fenice back soon - however, I won't have any HVAC.

My mechanic has about 3-4 hours of labor pulling out the dash and testing all the circuits attached to the switch cluster. He's not getting a good reaction from the buttons, and the Haynes manual (he doesn't have another) doesn't help with the wiring.

He is hearing some of the flaps open, but he really can't check them since the flaps are inside the heater unit.

So, anyone familiar with this? Of course you are - that's why I'm asking you. ;) Any ideas on where to start?

SBJ

[OperaHawk]

Update:

I found Betazag's thread from '06 with some ideas - any others would be welcome.

Thanks,

SBJ

[davidb]

Jesus Steven. Lotsa vacumn operated open/closure valves,
both heat + A/C buried, maybe 4 - 6? A miss connected or
NOT connected vacumn hose would be my starting point.
Thereafter bad valve? You're in Jim Keller territory here.
He is the GURU in this area. In all due fairness to Jim,
w/o your head in either footwell, pretty much everything
exposed, who the heck would know or diagnose? Conne-
ticut is a long way from Ohio. I don't think the Haynes
manual will help. You might send Jim some digi-cam photos
if you isolate the issue. He,above all,would know. Sorry.

[DJ]

FWIW, I would recommend tracing and closely inspecting the entire length of EVERY one of those vacuum control lines.

The reason I say this is because of the experience I had with my Scorpion when I first got it. It appeared that all of the lines were properly connected and in good condition. However, I still had lots of problems with the controls. After finally pulling and closely inspecting every line I found that almost every one of them had been chewed through by mice in several locations that are not visible during a cursory inspection.

[Will]

IMO you should be able to pull and hold a vacuum on each of the vac servo lines with a Mityvac, and ditto for the vac supply line from the canister if you lightly pinch off the hose coming from the canister with a pair of vise-grips.

You can usually see the "arm" of the servo moving, even when you can't see the air door. I run the blower to find out what the air doors are doing. If nothing seems to be coming out of vent on one side only, you may have dislodged the duct to the vent. That's happened to me a couple of times.

Oh yeah, good luck!

[Allen Lofland]

I took the enitire system out of the car and rebuilt it, but if thats a bit over the top for your plans. How about a parts car some where, get a ac-heater box and learn it on the bench. Other than that. head under the dash and see if the arms are moving when they should, this is easly figured out with some playing around with the push buttoms and what they say. Remember the Defroster will energize the AC compresor circut.
Haynes will not be of any help with this problem. New controls are available from Chrysler products if you get to them before they crash :(
Jim Fierst in Arizona, formaly whoa Brakes owner....just went thru his Zagato AC-Heat system and even found a updated increased volume blower fan that fits :) But again the box has to be out for that install......
Mighty vac idea is a real good one and if you stick your head under the dash you can tell a lot about what the doors are dooing but you cannt see if they are still sealed good or attached to the hinges :( most are in pretty good shape giver their age. I have rebuilt a couple Zagato box's and of cource the Scorpion and they are almost identical. There is a schematic of the Scorpion vacumm hoses and what they do some where around this site DJ where are they.

[SubGothius]

The very first thing to check (or just go ahead and replace) is the HVAC's main vacuum supply line coming from the cannister underhood. Actually, you may be able to get away with just splicing in a new section where that line runs across the firewall above the exhaust, as exhaust heat tends to degrade the rubber lines in that region. Been meaning to do this myself, just passing along what I've read before.

[Jim Keller]

Your description also leaves a lot to be desired! LOL, "it doesn't work" doesn't really tell us exactly what problem you have, is it no heat? no A/C? no heater fan? no air from ducts?

There is a mass of colored vac lines on the back of the control, but those you can't really screw up since they are on a connector. I replaced my black vac lines, (to box from canister and from box to heater control valve), when I took my box out as having the dash and box out made it a breeze to access everything, it's pretty much impossible to do it with the dash and box in as the one runs across and above the heater box.

There isn't much to the HVAC system that can be crossed up with exception to the wire connections on the back of the control unit, heater motor and fan switch, that can cause problems when pushing buttons on the control unit if you switch up those wires but the push buttons will still operate the air control flaps to distribute air to the location you have pressed as well as open/close the heater valve if the vacuumn is there. There are only two flaps, the one that takes in fresh air from the cowel and the internal one that directs the air from defrost to floor/dash vents.

The cowel vent is normally open except when you have the OFF button, MAX A/C and I think the defrost button pushed, it then recycles inside air, heat, vent and normal A/C should have the cowel vent in the open position mixing inside and fresh air.
Heat and Vent will have some air to the defrost vents as well as all dash/floor vents, Defrost will send it mostly thru defrost vents with some air thru dash/floor, Normal and MAX A/C is all dash/floor vents......I think! LOL

It is easy to get the vent hose ducts to the side vents disconnected/knocked off when installing the dash that will cause no air thru the side vents, but you should still have air thru the defrost, front center and floor vents as they duct directly off the box with no hose connections

Give us a better more detailed description and we can go from there

[OperaHawk]

You know, it's a miracle what this car is like with real brakes... :P

More news on the HVAC:

According to my mechanic (and a cursory inspection by yours truly), the hoses are all hooked up and look fine. The system seems to work - you hear the heater whir, and when you press the heater/defrost, heated air does come out. What's not working is any of the other vents, and my guy says it's due to the center console. It's not opening the correct doors. Also, I'm noticing that only the low fan setting works - the high setting doesn't work.

My guy thought the way to go would be to pull the console/controller from my donor car and see if that works better, but what's the routine in doing that?

SBJ

[SubGothius]

...when you press the heater/defrost, heated air does come out...Also, I'm noticing that only the low fan setting works - the high setting doesn't work.

That last bit suggests you may have the fan wiring mixed up, as Keller described. The rest of it suggests to me that the box isn't getting any vacuum or isn't holding any vacuum it's getting, so it can't move any flap doors at all. Don't worry about the colored hoses; they're not rubber and don't degrade (barring any rodential intervention ;) ), and are also unlikely to be hooked up incorrectly (unless you've eliminated every other possibility first).

First, try plugging the vacuum circuit between the box and heater valve, in case you're losing vacuum there; you can either pull it from the valve underhood and plug that end somehow, or better yet, pull that hose from the gizmo on the driver side of the box and stick a cap over that barb.

If that doesn't make any difference, try what I suggested with the main vacuum supply line running above the exhaust. Since completely replacing that line practically requires pulling the dash, and it's unlikely to have disintegrated inside the cabin, just find where it exits the cabin thru the firewall, snip it off an inch or two from the exit point (as close as is convenient at least), stick a coupling barb in the remaining stub and replace as much of the rest of the engine-bay side of the line as you can manage.

[Jim Keller]

I have never had the control switch assembly have a problem other than the heat control cable clamp post crumbling away and the cable coming lose, I highly doubt it has anything to do with the control assembly

However, with your last description, another common problem is the resistor on the right front strut tower right by the cowel that controls the fan speeds. It is small, about 3 inches by 1-1/2 with a perforated metel cover, open on each end, and a loop of hard wire running thru it with 3 wires attached held to the strut tower by one screw. If that is bad, that will cause the fan not to work on the higher speeds

No I am not sure how to test it without swapping in a known good one, sorry, but I do have a known good one, doesn't look all that great, (cadium platting is pretty much gone), but it works fine if you don't have one handy to try

The center vents will have the most air and unless you get the fan on a higher setting, you won't get much from the side vents or the floor vents on low fan.

Is it switching properly from front heat vents to defrost vents so far as air direction? if so, the internal flap is working fine and it is most likely only a fan speed problem you are having

[davidb]

In the download section is an A/C helper card for '79s. 3 pages,
color coded. Basically shows routing. Might be of help for
understanding what goes where. Just diagrams, i.e. no trouble-
shooting verbage.

[OperaHawk]

I knew I came to the right place! ;)

I'll let you all know how it comes out when I have some time to work on it. Currently, I'm just busy with auditions and my students.

HOW-ever, I'm walking around with a huge grin on my face now that Fenice is up and running! VERY happy camper...

More to follow.

SBJ

[OperaHawk]

Latest news:

Last time I was able to pull some things off of Uno, I grabbed the fan switch at the control unit. Just replaced it, and I now have a high setting! So everything in the 'guts' woudl appear to be good in that sense.

I'm getting air out of the defrost vents, but no soap on the other vents. I have yet to pull stuff apart and try all the stuff that's been recommended (auditions, teaching and such), but I'll keep you up to snuff on what I find.

Thanks - and Happy Holidays!

SBJ

[DJ]

I have yet to pull stuff apart and try all the stuff that's been recommended (auditions, teaching and such),

Someone actually recommended auditions and teaching before you try working on your car?

How rude! ;)

[Jim Keller]

Bare with me, I am typing my thougts as they come to me! LOL:
Sounds like a vac line is off or split/broken or possibly cross connected to the wrong port. If the supply vac line to and from the canister on the right front strut tower into the interior is fine, (I have never seen a bad line once inside the firewall to date, they normally only go bad out in the engine bay area due to the drastic temp changes and exposure to the eliments), then check the vac lines to the actuator canister on the left side of the heater box, make sure they are connected properly as that one controls the flap for the various vent openings.
The canister on the right of the HVAC unit controls the fresh air flap out in the cowel, which should normally be open unless you have the unit in OFF, Defrost or MAX A/C position. If the outside fresh air flap isn't opening and closing, you don't have vacuumn to the control unit, if it is working but the vents inside are not, something isn't hooked up right or broken to the actuator on the left side of the HVAC box

Keep in mind of corse, the car has to be running while doing the tests to have the vac to operate

All this talk about vac problems brought a funny image to my mind I thought I would share, I am old enough to have owned vehicals with vac operated windshield wipers as my daily driver, they ran really fast at idle, like sitting for a stop light, then when going thru the gears, they would almost stop by time the engine revs got to the shift point, nothing like driving in a heavy rain at speed with wipers that hardly move........talk about nightmares! LOL

[OperaHawk]

Jim:

The vac line from the bottle in front of the strut tower appears to be good - no apparent leaks. I'll get into it more as time allows.

Is there a diagram of any sort available for the vac lines under the dash? That would help me and my mechanic (would prefer to do it myself, tho.).

As for the defrost vents, everything checks out good there - the high setting works (as I said, thanks to a new switch), and it'll blow cold (AC, not needed at the moment) or hot. No difference whether set at Vent or Defrost. So it must be the plumbing, I'm thinking...

DJ - Yeah, but when you gotta go to NYC, you gotta go (took the silver bird instead of Fenice - wouldn't go NEAR Manhattan this time of year in anything four-wheeled unless it was a cab!)...

Thanks, folks.

SBJ

[SubGothius]

The vac line from the bottle in front of the strut tower appears to be good - no apparent leaks.
What test method did you use? Leaks aren't the usual problem with that hose so much as an internal collapse and consequent blockage due to exhaust heat; if that's the case, it will seem to hold vacuum/pressure but can't pass a vacuum signal.

I think Defrost is the default "at rest" mode when no vacuum is acting on any flap-door actuators. If the controller and box aren't getting vacuum and can't open/shut any flaps, then the system will remain in Defrost mode as a sensible fallback position.

[OperaHawk]

Considering it's hitting 90 here (and driving Fenice is a necessity right now), I decided to do what I can to fix the HVAC system. I started with removing the center control grill, and what do ya know - the flap over the system is not connected to anything, so it won't open! So I've propped it open for the moment - I'll see if I can find the real problem later. ;)

I'll fill you in later when I check the hoses to see if they're holding a charge.

SBJ

[davidb]

You sound like me: just one thing after the other. My blower fan
used to work. Now it's blowing it's fuse. If I gotta pull the instru-
ment panel [again] to get a good look off to the right, well.

[OperaHawk]

Now I have another question 'fer y'all,' as they say 'round here'...

I know that the defrost setting is the default for the vacuum tubing, since that was the only thing working. However, when I lifted the flap for the center stack, I had air blowing. Huzzah...

HOW-ever, I'm getting warmish air on the selector on full cold, and nothing cool from the A/C (mind you, I haven't checked what the system has in it yet). Is heat the 'default' setting for the HVAC, or is there another opening/flap/gizmo that isn't opening?

SBJ

PS: Jim, bear with me. I'll try to have the LANCIA badge in the mail for you soon...