64 AC : Blower runs, air is felt at firewall, but not through heater outlets or AC vents (HEAT/AC door WORKS)

[Norman Silverman]

Hello All.

As I am getting in to this troubleshooting with the benefit of Tim Groves invaluable book, I find something that is not covered; blower works strongly but no air can be felt either at heat ducts or AC ducts even though the Heat/AC mode door DOES WORK when I apply vacuum to the solenoid that controls it. (thanks to Tony and Ginny 429 for clueing me in to what panel to remove to observe the door). 

As luck would have it, I have buddies who own a MOPAR junkyard and one time they took in a 64 CDV with AC. So I managed to get some parts off of it to practice on and to use. I got what turned out to be a good Transducer and installed it, so now when I run the temp wheel the Power arm moves from AC to heat and changes the blower speed. HOWEVER, nothing comes out of anywhere even though I can hear the blower working hard AND I can feel a STRONG rush of air all the way in the back near the firewall. I had thought what I was feeling was the INTAKE for the blower with the RECIRC door stuck open (solenoid inop), but now I am not so sure. 

When I stick my hand inside the heat/ac blend door I can feel that something is flowing, but not alot; it sounds/feels like there's lots of air moving, but not in the right direction. 

Stumped!

All replies welcome, thanks.

Norm

[Norman Silverman]

Thinking about this a little more, the former owner let Curly, Larry and Surfer Dude try to fix the system. When I started to investigate after I bought it from him,  I found that they had left the resistor unplugged and un attached, plus they had one or two vacuum hoses incorrectly hooked up. IS IT POSSIBLE for the Blower Motor to be reverse-wired and run in the opposite direction? (Crazy, I know, but is it possible?)

[3n49omug8n28i]

The easiest and best way would to be remove the dash and glove box. Then trace all vacuum lines being sure they are routed correctly as per the shop manual. I would cut all the end of the original lines to get a better seal. You should have as close to zero vacuum leaks as possible. 

Get yourself a hand vacuum pump and check all mode doors for vacuum making sure that they dont leak. Also check the parking brake diaphragm for leaks. 

My car had the ducts rerouted by some dolts so this is also a possibility. Or the material ducts can be deteriorated from age and leaking.

[Norman Silverman]

Much appreciated, Clovis. I will check things out. FYI, I also cut the ends of all vacuum lines I can see, and for the same reason (same with those under the hood). How difficult/dangerous is it to remove the dash top? My car's interior is literally 100% perfect and I would not want to run the risk of cracking the dash top when removing it. Any tricks associated with removing it? (the glove box was the first thing I removed)

Norm

[3n49omug8n28i]

It's fairly simple to remove the dash top. I've had mine off half a dozen times. Three wires for the interior lights and dash comfort control sensor are mostly the pain part of it. Also watch that no hands go near the dash sensor grill while removing it. 

[Norman Silverman]

Got back to working on the AC Climate Control system today. When I took a real good look through the space where the glove compartment was all the way back to  the firewall (to the area where I feel the strong breeze) I have discovered that I can see the back of the AC Recirc door vacuum solenoid and its mountings and operating arm. That's the white solenoid that's  mounted in the engine compartment near the vacuum master switch. Is there a cover plate missing? I thought I'd have to take off the heater box cover in the engine compartment in order to get to it.

 

[3n49omug8n28i]

That looks like it. Good luck getting in there with any tools. I took off the cover in the engine compartment to change mine. I also installed a new blower fan motor while in there. I also removed my evaporator and cleaned it. It was one third plugged with junk and dust. All the gaskets were deteriorated so I made new ones for everything with different types of household door and window foam gaskets. Get the closed cell type they dont hold water. You can remove the passenger side inner front fender panel to access the whole a/c system. Remove the antenna once the panel is out for easier access. 

Just some suggestions as I dont know how far your getting into your system.

[Norman Silverman]

Thanks!! This may sound crazy, but I think the motor is wired backwards; strong air is coming out of where the recirc INLET is, when it actually should be going IN to the system from there. The only two possibilities I can at first think of for this would be power and ground reversed or motor cage assembled the wrong way (which I think may be impossible to  do). But after reading your response again, I thought maybe the evaporator AND heater core were both clogged up, which would cause the air to go back the other way. HOWEVER, even when I put vacuum on the heater blend door to get it to open to the vents, there's no real breeze to be had. 

I don't have the physical stamina to go in to the system as deeply as you did, so I am going to try to first replace the Recirc solenoid from the back. Then, try to track the blower power connection to see if it is backwards. If not (and if nobody tells me I'll blow the motor by trying it) I will reverse the connections on the motor and see if I am correct that it is running backwards. What else would explain why a STRONG stream of air is coming OUT of the RECIRC INLET, a place where air should be going IN. 

Stumped.

Norm

[3n49omug8n28i]

You won't hurt the blower motor. These systems are not complex but there is enough things to go wrong after 50+ years. Trying to fix it part by part is probably won't be a resounding success story. But not knowing the overall condition of the car this is my best advice 

[3n49omug8n28i]

Tony is correct only a power wire. Thanks I forgot about that. It cant be running backwards

[Norman Silverman]

Looks like Tony's "blocked passage theory" is gaining credibility by the minute. 

[Norman Silverman]

Just to be clear, this car did sit for a while but after being properly polished out this car will appear to have been built last week-it is that nice. The interior has NO signs of wear anywhere (plastic covers since new), nor does the chrome or glass. The engine compartment is exactly as it should be (including plastic washer reservoir and factory original battery cables)  with no mickey mouse bypasses, etc. The car starts instantaneously and runs as new in all other respects (original carb) and the windows go up and down at warp speed. The only things I had to do when I got it was replace the exhaust system and remove/clean/lubricate the power seat transmission. 

So, I am actually a bit stumped as to why this system is not operating properly-especially why the recirc inlet is actually acting as an outlet for a strong stream of air from the blower. Squirrels or other varmint's nest? Maybe, but there would likely be an odor associated with that-and there isn't, plus none of the vacuum hoses are nibbled.  The heater setting yields no air, either so blockage still could be a good possibility. I have a small TV camera with a foot and a half lead-I'll try to probe the areas that way to see what's up.

THANKS!!

PS Everything on any old car I have has to operate properly, that's been my long time rule-especially air conditioning here in San Diego (although it is not a warm as most folks think it is here).

[3n49omug8n28i]

Norman check the power servo for operation and the transducer. The transducer can get dirty from sucking air through it with the vacuum. Mine was dirty and allowing full vacuum through it. If I remember correctly a full vacuum causes full heat with the blower on high speed. I dont have my manual with me as I'm at my summer place. Mark may be able to pipe in on that.