DustyMKE

1997 HONDA CIVIC EX:

Issue: Air/Heat not coming through vents as strong as it should.

Changes made: Blower motor replaced-working, Resistor replaced-working

Ideas:
-Cabin filter clogged-to the best of my research this generation did not include a cabin filter

-Blend door/doors not fully closing somewhere in the system so as not to allow the full air pressure to make it through the vents.

Request:
Pictures or instructions on where to locate said blend doors or other areas to check for obstructions or leaks of air pressure.

Thank you for your time.

Pics of system available if requested

ezone

Was this a factory part?
Did you have to modify wires to make it work?
Is the fan blade identical to the original, diameter/height/blade pitch and direction?

Is the fan spinning backwards? THAT will keep it from blowing air properly!



You are looking for low pressure/high volume leaks.


If you don't have good air flow from the dash vents, do you have good flow at the floor or defrost vents when those positions are selected?
Are the dash vents open or closed?


Air leakage (external) would most likely happen between the blower housing/evaporator housing/HVAC case. You should be able to feel leakage (wind) with your hand if it is significant enough to cause a loss of flow to the vents.

DustyMKE

Was this a factory part?
No it was a autozone generic model.

Did you have to modify wires to make it work?
Yes i had to cut the female connection off and wire the motor to the power.

Is the fan blade identical to the original, diameter/height/blade pitch and direction?
I was able to use the same wheel that came on the original factory part.

[B]Is the fan spinning backwards? THAT will keep it from blowing air properly!

I thought about this while installing it. But how would that be possible? Would incorrect wiring cause the motor to spin in reverse?



You are looking for low pressure/high volume leaks.
I think at this point I am looking to locate the blend doors inside of the dash so i can find which one is not closing off to divert air.


If you don't have good air flow from the dash vents, do you have good flow at the floor or defrost vents when those positions are selected?
Are the dash vents open or closed?
Dash is closed and the pressure does not change throughout.
It would be as though the blend door would change positions yet the other positions would still be on. i.e. if the dash was selected, there would still be flow through the floor and defrost.

Air leakage (external) would most likely happen between the blower housing/evaporator housing/HVAC case. You should be able to feel leakage (wind) with your hand if it is significant enough to cause a loss of flow to the vents.

After the snow storm i will be opening up the housing to rule out any blockage. As far as tonight i have enough flow to defrost and get to work, however I have never been one to quit half way through a project.

I appreciate the time you have taken in this matter and all suggestions and ideas are welcome as I feel I am running out.

ezone

Did this problem start just after the fan motor was installed? Or when did the problem begin?



Absolutely. Switch the 2 wires at the motor and see what happens.

Quote:

You are looking for low pressure/high volume leaks.

This is why I asked about floor and defrost airflow.

If you DON'T have good air flow in those positions either, then the problem shouldn't be in the doors.


Got a dog that rides in the car a lot?
I got a GMC truck with a zero airflow complaint....turned out to be dog hair clogging up airflow through the evaporator core. Guy always had his German Shepherd riding in the truck.



FYI: Technically, the blend door is the one that controls temperature.
Mode doors control where the air flow goes (floor/dash/defrost)

Is there any change at all as you select various positions?
Since there are several pieces of linkage attached and operated by a single actuator (mode actuator), could one of the links be stuck, detached, or broken?


What I would do is sit in the car with radio off...
Fan on full blast.
Listen carefully: You can (should) hear the airflow change as the doors move.
Select recirculate, and wait for the sounds to change.
Select fresh, and wait for the sounds to change.

Select hot, and listen for the sounds to change.
Select cold, and listen for the sounds to change.


Do the same for each mode position, move across punch one button at a time and listen for sound at each position to change.

Floor vents will blow and shut off?
Defrost vents will blow and shut off?
Will dash vents do the same?

Does the mode control motor run all the way to the full vent position, or does it stop too soon?
There's an entire flowchart for testing the mode motor and all that stuff.

Mode motor is on the drivers side of the HVAC housing, you can lay on the drivers floorboard and look up to find it. You can watch it operate, you can watch most of the linkages move as it operates too.

Thoughts, HTH

DustyMKE

Thank you again for the troubleshooting.

1. Problem began before the motor died. Clicking noise was observed and then the motor died a few trips later. Small leaves and seeds fell out as the motor was removed.

2. Spinning backwards; I will remove the motor and check the direction and redo wiring to see if direction changes.

3. I have a German Shepherd mix that rides with me everywhere. This seems to be on the money as I have yet had a chance to take a look inside the HVAC housing. My hunch is that you are correct in this assumption as the dog sheds very much.

4. I have located the blend door and observed it working correctly after a linkage was put back on track. I will locate said mode doors, now that I know where to look and observe the transitions.

Again, I appreciate your continued support in this matter and I shall do my best to continue working on this issue. I have enough air flow to defrost and operate in these winter conditions and I will post updates as soon as I am able to run through these ideas.

ezone

Since these cars don't have a cabin filter, any debris that gets past the fan blade (wheel) will end up trapped at the evaporator core, if it is too large to pass through it.


It's a permanent magnet motor. Reversing polarity will make it run in the opposite direction.

Just make sure it spins the correct direction....., which leads me to the next item:
When you drop the fan out, take a mirror and flashlight (got a periscope?) and see if you can get a view of the evaporator core.
Or maybe stick your hand up in there (toward the drivers side) and feel for a layer of hair covering the surface of the evaporator core.
That would tell you if this is where the blockage lies!

If this is the issue (I'll assume it is for the moment), the blower housing can come out of the dash (with a lot of work) and you could reach a good part of the core with a shop vac and maybe some creative tubing/nozzles, cardboard and duct tape.

The evap housing can come out of the dash as a unit, but that would entail discharging and recharging the AC freon to do so. It is between the fan housing and the Heater housing, designed as a separate and self contained unit.


On the GMC problem I spoke of -- I was able to access the 'aft' side of the evap core with a blowgun to clear the majority of the obstruction (fan removed).

HTH