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Discussion Starter #1
Dear friends,

This is a RHD model and I removed the instrument binnacle to fix some non operating warning lights.

I had this problem with air distribution. Air comes mostly from top vents to windscreen and a bit towards front. This is a problem because cold air makes windscreen condense from outside so I have to use wipers on hot sunny days.

With the instrumentation out of the way, the stepper motor socket is accessible to me. Is it possible to provide 12V and grounds to certain pins and make the steppers function? Because I am not sure about the control panel as well.

Is anyone here knowledgeable about the pinout of the stepper motor socket?

Thank you

Kind regards

Tharanga


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DO NOT turn key to acc. with binnacle removed or you could set off your air bag light. Did that in error now I can't clear the darn thing. On a 95, there is a lever on the outside of the airbox, visible from under the plastic cover at the wipers, on the left side (so, engine compartment, not inside the car). If the lever does not move in and out as you increase-decrease temperature, the inner flap could be broken. If it does, could be a stepper gear. For that, I have no idea as the systems seems to have been revised for the newer models. Check that lever first as it could save you much work (until you decide to repair it).
 

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Discussion Starter #3
Mine had the heater core already removed as this is a tropical country. So temp control does not happen. Air distribution is the problem. It used to work but dunno what happened to it. It was out of road for a long time and not sure what the mechanic had done to it.

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The air distribution is controlled by a rotating drum. It is the deeper in of the two stepper motors. Assuming the electrical connector is working then the possible failure is of the end of the drum, known to develop cracks. The fix involves removal of the stepper and installation of a metal reinforcing ring onto the end of the drum.

The lever arm referred to in another post on this thread controls the position of the air blend flap mixing ambient and AC cooled air with air passing through the heater core. Your heater core isn't there so the position of this flap wouldn't be important to the operation of your cabin ventilation system.
 

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Discussion Starter #5 (Edited)
Is it possible to take out the stepper assembly without taking out the complete dashboard?

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Discussion Starter #6
Tomorrow i would check whether the stepper socket receives power supply from the control unit. Not sure which pins should give what. The Cardisc only shows the connections to the control panel.

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The air distribution is controlled by a rotating drum. It is the deeper in of the two stepper motors. Assuming the electrical connector is working then the possible failure is of the end of the drum, known to develop cracks. The fix involves removal of the stepper and installation of a metal reinforcing ring onto the end of the drum.

The lever arm referred to in another post on this thread controls the position of the air blend flap mixing ambient and AC cooled air with air passing through the heater core. Your heater core isn't there so the position of this flap wouldn't be important to the operation of your cabin ventilation system.
Well, there you go.
 

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Is it possible to take out the stepper assembly without taking out the complete dashboard?

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This thread says RHD has two separated steppers:

https://www.alfabb.com/bb/forums/164-168-1991-1995/512650-164-b-air-distribution-motor.html

The one you need to access will not have that Bowden cable attached to a lever arm. That one moves the flap by means of the Bowden cable passing through the firewall and connecting to the lever referred to by beeton.

I'm guessing the one behind the speedo is that one. The one visible in your photos looks like the distribution drum motor you need to check for operation. It's gear drive fits over the end of the air distribution drum so it may not look as if it connects to or does anything. The rotation of the drum is not visible. You verify movement by checking airflow at the vents. In sequence, defrost/mixed defrost and floor/mixed floor and face level vents/floor. As the drum rotates it covers and uncovers ducting that directs airflow to the defrost/floor/face level vents and does so with overlaps where air gets directed to more than one level of vent simultaneously. In fact, air flows through all vents continuously but the drum directs the majority of air flow in the sequence I describe. Clever and works the same with manual control versions just as it does with steppers.

LHD cars have both steppers on one metal bracket and it cannot easily be removed with the dashboard in place.

This thread used to have photos for both RHD and LHD versions (NZ is of course RHD). Maybe Alfisto Steve can resurrect the the photos somehow.

https://www.alfabb.com/bb/forums/164-168-1991-1995/15701-photos-164-stepper-motor.html

This thread deals with LHD

https://www.alfabb.com/bb/forums/164-168-1991-1995/379737-164-stepper-motor-assembly-refurbishment.html

And these are more links courtesy of Alfisto Steve

https://www.alfabb.com/bb/forums/164-168-1991-1995/141647-alfa-164-alfisto-steves-maintenance-tips-16.html#post1178016
 

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"Is it possible to take out the stepper assembly without taking out the complete dashboard?"

First of all most of the links posted so far on this thread pertain to the LHD pre-facelift car. They don't apply to your car.

Yes, it's very easy to remove the air distribution stepper assembly without taking out the dashboard.

The most pertinent thread on the AlfaBB is:

https://www.alfabb.com/bb/forums/164-168-1991-1995/667304-24v-164-convert-manual-air-con-climate-control.html

Begin around post #87.

DanNZ hopefully will read this and give you some suggestions, or better yet, send him a PM.
 

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Discussion Starter #10
Touched the visible stepper and operated direction buttons. The stepper buzzed and stopped for each button. That means both the control panel and the stepper motors work. Lots of reading to follow

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That's the air distribution stepper, the one you wish to test.

If the cabin air fan can be operated and the stepper operated you can determine if the drum is changing position properly by checking for the airflow from appropriate vents in sequence.

There is the caution elsewhere in this thread about powering up the electrical system with the airbag disconnected. This will trigger the airbag fault light which then will need resetting when you put the wheel back on.
 

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Discussion Starter #12
Yes I always make sure the instrument binnacle is connected when turning on power. Which I did. Unfortunately the air direction does not change with buttons pressed but they surely makes the motor buzz and park. Now in the process of removing the motor assembly and stuck with the innermost screw. Definitely need an offset screwdriver.


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Greetings
Take a look at my thread referenced by Pinino above. It’s easier than you would think to get the front screw out with a 1/4” drive universal joint on a long extension and a philips bit. Getting the screw back in is much more difficult, I’d replace it with a screw with a hex head if you can find such a thing. I managed to get the original screw back in but it took a lot of super-glue to keep the screw on the bit and a lot of trial and error to get the angle on the universal joint just right with tape! You also need a good head mounted flashlight and another directed from above. Being physically flexible is helpful too - I was pretty achy for a day or two after! Overall much easier than pulling the dash!
 

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Discussion Starter #15
Hi Dan,

I know there are only 3 screws and there is a broken spindle to expect thanks to your post Pinino shared the link to me. I should say alfisti are the most helpful people on earth
I dont have a universal joint and i am looking to buy this tool. $3.5 on eBay. Would be easier to put the screw back from it as well


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Unfortunately I don’t think that would fit. Just search for 1/4” universal. You have to approach from the driver’s footwell at approximately a 120 degree angle.


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Discussion Starter #17
Yikes, is that so? I tried looking from driver's footwell. Could barely see it. Hmm..should try that way then. Got to find the tools you used then.

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Once you have the bit engaged in the screw look from the front again while unscrewing with your right hand from the footwell. Once you get the hang of it it’s not as hard as it sounds.


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Hi Dan,

. . . there is a broken spindle to expect thanks to your post Pinino shared the link to me. I should say alfisti are the most helpful people on earth
Maybe, maybe not. Broken spindles are commonplace on the pre-facelift cars, but facelift cars have been programmed better in the sense that less torque is supplied to the gears and spindle. Before Dan completed his project I was only aware that the later HVAC supplied half as many impulses (resulting in less wear and tear on the gears, etc), but seeing a video that Dan sent me, it's obvious that the later HVAC stops sending power one second after the arm reaches its stop, while on the pre-facelift, the motor stops three seconds after the arms hits the stop. Facelift HVAC = a lot less stress.
 

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Discussion Starter #20
Alright!!

I took a gynecologist's approach towards the air distribution problem.
As you would see in the photos, I went through the mid air vent.
Managed to squeeze my phone in to take pics and my hand inside to feel the air distribution drum.
With fingers, I did swing it upwards but it came swinging down and it did rest with the flat surface facing upwards and curvy surfaces facing downwards. (COG dictates)
Does that mean the stepper motor spindle to the drum has broken?
Or would stepper motor rotor just rotate freely without any resistance if you rotate it manually?


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