alfapro.com - Steppers & Gears Discussion 2000

Steppers Gears Discussion 2000
Postings from the Alfa Digest and 164 Discussion Forum (some material has been edited for relevance and brevity).
See also the Discussion 1998-99 and Discussion 2001

Subject: Stepper motor clicking ... Name: Dale Daniels Time/Date: 02:34:00 2/24/2000 My 90 164 has started the dreaded stepper motor clicking ... I have unplugged the motor inside the panel from the glovebox (temp control motor) and the clicking stopped. What and how does this motor control the heat ? Can I remove it via the access hole for service? Thanks Dale. ------------------

Subject: Steppers Name: Peter Greis Time/Date: 04:56:29 2/25/2000 The ACC has two stepper motors, temp and distribution, and both use the connection you unplugged. Better change the settings manually and feel if they work ok or listening if the click stops. The temp stepper is located close to the access door but I doubt that you can service it though the hole. You do know about the metallic gears, no? Look at http://www.AlfaPro.com ----------------

Subject: Steppers Name: Alex Time/Date: 05:17:45 2/25/2000 Dale, I tried to access the motors throught the glovebox opening but had to give it up eventually. You can get the motor closest to the opening (temperature) out if you bend the bracket and separate the motor from it. The problem is that straightening the bracket sufficiently to allow for proper installation of the new motor is hopeless. When I realized this, I gave up on the distribution motor closest to the engine bay. My mechanic replaced the assembly in 6 hrs exactly. He didn't take out the whole dash but loosened it enough for him to pull it out in the right side (while in the passenger seat), rest it on his knees, and replace the motors. You should have seen it, it took him about 1 hour to reach a stage at which he could remove the old steppers. Reassembly, however, was slightly more time-consuming. If you have the heart to do it, cutting a service door in the side of the glovebox may proove an interesting option. Operating from that side, it should be a breeze removing the motor asembly. Good luck! - Alex, DenmarK, '93 QV ---------

Subject: Stepper Motor? Name: Ross Time/Date: 16:37:09 3/02/2000 I have a 1991 164 that I have owned for 1 year. The car has had no history of stepper motor problems that I am aware of. However, in September after of a problem free summer of air conditioning, I turned on the heat/defroster for the first time in several months. The system made a nosisey racket (gear stripping/vibrating sound) followed by a shorter version of the same sound about every other second or so. Since then, I have had no directional control of the air flow. I must keep it in ECON - defrost mode. As soon try to change the direction of the air flow, the system makes the same noise for about 5 seconds, followed by the sorter version every other second. I should mention that I have control over the temperature, just not the direction of the air flow. Does this mean that the stepper motor requires replacing? Could it be anything else - that doesn't require ripping the dash apart? Thanks for your help. ------------

Subject: stepper motor Name: Neil Choi Time/Date: 16:47:02 3/02/2000 Yes, your air distribution stepper needs replacing, get those replacement brass gears from Stuart Heather (AlfaPro). Do both steppers and install the reinforcing ring on the AD drum (a bit of 19mm id pipe will do the job) while you have the dash out of the car. Have fun, Neil ----------------------

Subject: stepper woes Name: Christian Time/Date: 17:45:02 3/02/2000 I noticed that there are two stepper motors. One controls the direction of the airflow and the other controls the temperature. The gears in each motor move to make adjustments are made to the airflow and temp. In theory if one keeps the airflow and temp in a constant state the gears should not move at all. Does that mean for example if I set the airflow at 2 and temp at a steady 21C and never change them the motors should last much much longer? --------------

Subject: ACC and steppers Name: Michael Smith Time/Date: 20:46:57 3/02/2000 That's not how it works at all, it's not just an automated manual system (although it looks that way). The ACC tries to match the temperature setting you select, by distributing air throughout the cabin in an orderly way. There's a cabin air temperature sensor (in the overhead console, left side for NA cars) The sensor feeds a signal to the ACC which opens the air blending flap to allow warm air into the cabin, gradually closing the flap to allow a higher proportion of cooler outside air to be mixed with the warm air passing through the heater core. As the interior warms up to the selected temperature the air blending flap closes the heater core off completely to incoming air, the coolant continues to flow at the same rate through the heater core. The air distribution drum responds to a different portion of the ACC programming and selects vent or heat or defrost as the ACC senses they are required. Selecting a particular air distribution will stop that motor from operating, there's no way to stop the air temperature (blending flap) motor from operating. The ACC even continues to send a pulse to the stepper when "off" is selected!

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Subject: constant state of steppers Name: Neil Choi Time/Date: 18:33:37 3/02/2000

I don't think setting the airflow SPEED constant ie 1-4 will

preserve the stepper gears. The air distribution stepper moves the AD drum around to direct airflow ie to windscreen, feet or face. It is these back and fore rotational movements which cause the wear on only a few teeths of one of the plastic gears in the stepper gearbox. Unless you set the airflow direction contant and never change it, such as at the windscreen for defogging, then your gears will wear out over time. The air temp stepper doesn't seem to wear that much, not in mine anyway or a couple of other 164s I have seen or heard about. -----------------

Subject: Stepper Motors Name: Jerry in Houston Time/Date: 14:24:21 3/05/2000 It would be interesting to know/speculate which settings put the least amount of stress on the stepper gears (the real problem, not the motors themselves) I keep the system in the manual mode and individually select the speed and distribution as needed on my US spec 93 164L.So far I have no indication of stepper gear failure. Jerry in Houston -----------

Subject: stepper Name: Del Time/Date: 01:47:57 3/06/2000 Yup, Jerry, I do the same thing. Everything manual (my dealer says I'm fooling myself, that the temp stepper still does its' thing); of course, in Seattle the weather is so mild most of the spring, summer and fall that it wouldn't change anyway, I would guess, since I set it at LO and forget it. Have 75,000 miles on the S, and so far, knock on wood, everything is ok. -------------

Subject: stepper Name: Mark Time/Date: 21:36:19 3/05/2000 Jerry, How many miles do you have on your car? I have a 91 164 with 65000miles and I also always use the manual HVAC mode. Knock on wood but no problems so far. The auto mode must put a lot of stress on the gears. On a hot summer day here in Connecticut, the HVAC will automatically go the maximum fan speed which makes the car sound like a jumbo jet on takeoff!! --------------

Subject: stepper motor Name: RK Time/Date: 17:04:23 3/06/2000 Go to this site and check out everything you need to know about the stepper motor on 164s--- RK http://www.AlfaPro.com/ ---------------

Subject: Steppers Name: John Time/Date: 23:04:54 3/06/2000 Interested to read the comments from Michael about the constant pulsing of the steppers. I can hear a faint rhythmic clunking - about 1 clunk per second - from my steppers. This clunking is in perfect unison, and very faint so that I can only hear it when the motor is mot running and I'm parked somewhere quiet. Is this the pulsing from the ECU that Michael talks about? My 1989 RHD model has the A/C control that can never be turned off. The steppers works fine - I have not had any problems with them, but there is evidence in the car of the dash being removed at some stage, so obviosly a previous owner has had them replaced. Also would be interesteD if anyone has details or experience of easy replacement. Regards, John, Sydney Australia --------

Subject: Stepper Motors Name: Stuart Thomson Time/Date: 00:12:24 3/07/2000 The faint clicking is indeed the stepper motor pulsing. When they fail they become quite noticeable. I replaced the stepper motor gears in mine although they still worked well, as I had to take the dash off to get at the distribution drum anyway.... Cheers. Stuart T ---------------

Subject: Stepper motor failure? Name: Mark Brewer Time/Date: 16:19:53 4/13/2000 Message:

I think I have the dreaded stepper motor failure, but I thought I'd get some confirmation before I get the parts and clear the time to fix it.

The symptom is that I have no hot air from the A/C. I get plenty of cold air, and it can be directed wherever I choose. The problem was intermittent for a couple of days, then the heat was completely gone. I have had none of the clicking noise that everyone else seems to report.

I've read all I can find on this Web site regarding this topic. My understanding is that there are two motors in the stepper motor assembly, and that one of them controls the hot/cold air mix. Could there be any other reason other than the stepper motor that I don't have heat?

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Subject: The Fix !!? Name: Mark Brewer Time/Date: 14:43:26 5/22/2000 Message:

I unplugged the power to the stepper motor, and then plugged it back in. I have heat now. While I sincerely hope my little problem is solved, something tells me that there is something else awry somewhere. Thank you all for your help. Mark Brewer ---------------

Subject: Stepper Motor Name: Mark Brewer Time/Date: 15:51:53 4/14/2000 Message:

Thanks, Michael and Alex. The self test showed no errors. I couldn't identify anything behind the access panel in the glove box that looks or acts mecahanical (I have a '92 L, US version). I did find the plastic lever and the attached rod, wich appears to be extended towards the front of the car. I couldn't get it to move one way or the other, so I wasn't able to confirm whether or not there's heat. But it certainly looks like something mechanical is broken or jammed. ---------------

Subject: ACC Name: Michael Smith Time/Date: 18:41:11 4/14/2000 Message:

And one other thing. When the car is shut off the heat closes to cold position and the recirculation flap also closes, automatically. Don't try to move anything manually with the car shut off as it is designed to seal off the HVAC while the car is left unattended. ---------------

Subject: ACC Name: Michael Smith Time/Date: 18:38:59 4/14/2000 Message:

All the way forward means the heat is shut off, you are getting only outside air through the heater, unheated (obviously).

If the steppers are shot you should hear a click or tick sound from the stepper motor at the "front", ie the one closest to the back of the dashboard, closest to you in other words as you peer into the black hole you uncover when you pop out that useless little inspection hatch. Actually, the hatch is to allow replacement of the other temperature sensor which also is known to fail. This one tells the ACC what temperature the mixed air is, and is inserted into the outflow stream of air coming from the heater box into the distribution drum. But, the self test should have revealed this fault if this is the problem.

Sounds like you may have a mechanical fault which might be fixable. Can you move either end of the cable? Be careful not to stress the plastic actuating lever in the engine compartment, they break.

Inside the car you should be able to hook a finger around a white plastic actuator arm just inside that inspection hatch and pull towards you steadily and firmly which should open the heat flap a little, all the way back is full heat. It is feasible to block this in the open position but only if your steppers are already shot, blocking it when they are working ok could cause them to strip!

With the inspection hatch open and the car running select HI temperature on the ACC and observe the cable/lever either inside the dash end or the other end in the engine compartment , it should move. If the steppers are stripped than the arm should move a little easier by hand than if the steppers are OK.---------------

Subject: ACC Name: Michael Smith Time/Date: 18:29:34 4/13/2000 Message:

Also check that the cable is still connected at the heater box end and that the plastic lever is intact, these are known to break. The lever can just be seen on the passenger side of the firewall about the center of the car with the hood open of course. use a flashlight (or a torch if you're British, Kiwi or from Oz) as it can be hard to see.

Another possibility is the cabin air sensor located variously depending on model year and market. for NA this resides in the roof console, driver's side behind the pry off plastic grille. Use the ACC self test diagnostics first of all. Read the codes and post someone will look them up for you. ---------------

Subject: Steppers Name: Alex Time/Date: 17:42:01 4/13/2000 Message:

The stepper closest to the pass. compartment is the hot/cold mix one. Pry off the small plastic cover inside the glovebox to see if the motor arm is moving when you "turn on the heat" so to speak. The motor arm is attached to a small piece of piano wire that it pulls and pushes to control the mixture. If you take this wire off the arm and pull it towards you as far as it will go (not 100% sure which direction means hot, but I think this is it - alternatively, push it all the way forward), the heat should be at max and you should be able to tell if heat is generated at all. Good luck! Alex, Denmark '93 QV ---------------

Subject: Heating Name: Aaron (New Zealand) Time/Date: 04:48:44 5/23/2000 Message:

The same thing has happened to my 1990 164 3.0. The steeper motors are working but no hot air comes out of the heating system. I tried the HVAC system check and everything comes up okay. I have made an appointment with my Alfa mechanic next week and he's going to see what he can do!!

Subject: steppers Name: Frank Time/Date: 11:29:46 5/23/2000 Message:

Mark, I had the same thing happen about two weeks ago (coincidence?) to my 91S. I removed the inspection cover and could see the stepper and the arm and the control rod for the air mixture control (temperature). It was stuck all the way forward (cold). I tried to move it by hand but it would n't budge...so the stepper gears are OK (I hope). I figured I might be able to get the pesky little motor out through that inspection hatch so I spent an hour pulling and prodding but to no avail...I put the motor back in place and fired her up to confirm that things were still attached, and all of a sudden I had it working again. Problem was though that I didn't have the little plastic indexing clip back in its slot so I put it back into place (with a "click") and it got stuck in the cold (forward) position again. Got me thinking so I removed the motor from the bracket and secured it next to the metal bracket with a tie strap and it works now. So in summary I essentially rotated the stepper motor slightly so that the black plastic index clip on the bottom of the motor is resting next to the metal part of the bracket that it is supposed to fit into. I don't know of the long term problems yet but it works now and I am happy! ---------------

Subject: Heater. This weekend, i finally got around to replacing the heater core in *my* 164... ('92, w/155k miles). w/the help of the shop manual, printed out from the car-disc cd, i was able to pull the heater core out in 3 hours. i was quite pleased w/this, as all sorts of stuff has to come out 1st - driver's side wiper arm, everything removed from the mini-fire-wall, removal of mini-fire-wall, removal of a/c box, removal of hvac fan. access to the screws on the mini-fire-wall is *not* easy! wooda prolly had everything back together in ~3 hours, too, but upon removal of the a/c box, ewe can see the back of the dreaded stepper-motor ass'y. of course, these have been shot on my car for ~2 years, and as i have a gnu set, & also a set of those aussie metal gears, i yust *had* to go for it. so, i pulled off the glovebox (a real pita, cuz i dint print out anything from the car-disc for this), then proceeded to cut a hole behind the glovebox, to access the front of the stepper ass'y. ( i should have foto's awailable via email of this *hole* tomorrow, if anyone wants to see). well, i now have ~9 hrs total into it, and everything's almost buttoned up. another hour should do it.

if anyone needs stepper repair only, i tink it's still easier to remove the a/c

& cut a hole behind the glove-box, than to remove the entire dash. be sure ewe have the freon removed from an a/c freon recycler! if yer gonna replace the heater core, mebbe now's the time to upgrade to those metal stepper gears, even if yer plastic ones haven't yet gone away... doug "two-fer-one" sedon --------------------

Subject: Steppers From AlfaPro Name: Don F. Time/Date: 07:20:52 10/06/2000

I quickly skimmed through the tech notes and prior posts and did not seeanyone that had experience buying/using the replacement stepper gearsfrom AlfaPro. Mine sound like they are on the way out. Any advice wouldbe appreciated. Regards, Don -----------------

Subject: AlfaPro Stepper Gears Name: Kim (of Wis) Time/Date: 09:05:0610/06/2000

Don, I put a set of the gears in over a year ago. The replacement gears fitperfectly and have performed flawlessly. The process of opening up thedash is a bear, however, and I strongly recommend the use of the CarDiskVideo CD in a laptop next to the car. Contrary to what I've read, the metal gears are not louder than the original plastic, in fact, only a slight hum is audible when one makes a full-range shift.Kim (of Wis) '91B & '91 ----------------

Subject: Click, click, click.... Name: DM Time/Date: 13:09:22 10/11/2000

I too replaced my stepper gears last year. As noted, swapping out thegears is easy, getting to that point isn't. You really need the CD/videoto do it. Get a bunch of Dixie cups and a few Post-its to keep track ofthe 50 odd screws and bolts you'll remove to get to the steppers. As it was, my drum is what had really died, but not knowing that beforehand, I went ahead with getting AlfaPro's gears. Now I'm set for life,hopefully, in the HVAC department. When you do it, do the drum reiforcement bit too (it's easy and verycheap). And if you wait too long and the drum receptor cracks, and thenfalls into the drum, try vacuuming the piece out from the mixing box(going down the big center vent with the drum indexed) - it worked for me! -----------

Subject: Stepper Motor Gears Name: Dale Daniels Time/Date: 07:16:16 5/23/2000 Message:

I have managed to remove the stepper motor that controls the heat flap from my car and disassembled it (and people hassle the electrics in Italian cars - this parts German!) It appears that one of the nylon cogs has been stripped of teeth - where can I get metal gears to replace this with ? Can you buy replacement gears only from Alfa ? Thanks Dale. PS is it possible to complete this using the access panel in the glovebox - anyone need help with this let me know. -----------

Subject: Stepper motor gears Name: John Ring Time/Date: 16:52:50 5/27/2000 Message:

I,ve just bought and fitted the AlfaPro gears. They are excellent, well made from bronze and steel. Their service is first class.Incidently you can remove the complete hot/cold stepper motor through the glovebox removable flap,if you can take off the spring clip retaining the operating cable. -----------

Subject: Stepper motors RHD cars Name: Richard Time/Date: 06:27:58 5/28/2000 Message:

Given that the glovebox is on the other side on Right Hand Drive cars, does anyone know if there is access to either motor with these cars? Thx Richard Cambridge (UK) -----------

Subject: Steppers Name: Alex Time/Date: 05:34:20 5/24/2000 Message:

Did you manage to get both steppers through the flap in the glovebox or just the heat regulator stepper? Alex, Denmark '93 QV -----------

Subject: Steppers Name: Dale Daniels Time/Date: 17:36:45 5/24/2000 Message:

Just the heat controller ... -----------

Subject: Stepper replacement through the glovebox Name: John Wiltshire Time/Date: 04:14:27 5/24/2000 Message:

Dale, Would love to know how you did it! Thanks, John -----------

Subject: Heater Stepper Motor Replacement Name: Dale Daniels Time/Date: 17:45:28 5/24/2000 Message:

John. Inside your glovebox their is a small panel (at the font r/h side) pop this off and you will see the stepper - at the rear of the stepper motor (there is another access hole on the side (top) of glovebox) there is a retaining plastic clip similar to the ones that hold electrical plug connectors in - you can with a bot of dexterity unclip this clip and the stepper assembly with drop down. Then undo the two small screws at the front of the metal bracket - then you need to carefully prise the top part of the stepper gearbox (the odd shaped plastic box on top of the motor (cylindrical silver units) to do this get a small screwdriver and push gently at the edges - so the top of the stepper gearbox stays attached to the steel bracket (as well as the plastic actuator arm) Then you can carefully pull the lower part of the gearbox through the gap between the bracket and the glovebox and then through the access hole - now you can replace the gears - do the reverse to reassemble - it's a tricky job took about 1/2 hour to complete. - Cheers Dale. -----------

Subject: Stepper Motor gear replacement Name: Drew Time/Date: 08:10:04 5/23/2000 Message:

Dale, Go to www.AlfaPro.com. They have metal replacement gears for your stepper motor. I have not purchased any yet, but will be soon. Let me know how you make out. Drew 85 spider veloce 91 164S -----------

Subject: Steppers From AlfaPro Name: Don F. Time/Date: 07:20:52 10/06/2000 Message:

I quickly skimmed through the tech notes and prior posts and did not see anyone that had experience buying/using the replacement stepper gears from AlfaPro. Mine sound like they are on the way out. Any advice would be appreciated. Regards, Don

Subject: AlfaPro Stepper Gears Name: Kim (of Wis) Time/Date: 09:05:06 10/06/2000 Message:

Contrary to what I've read, the metal gears are not louder than the original plastic, in fact, only a slight hum is audible when one makes a full-range shift. Kim (of Wis) '91B & '91L -----------

Subject: Click, click, click.... Name: DM Time/Date: 13:09:22 10/11/2000 Message:

As it was, my drum is what had really died, but not knowing that before hand, I went ahead with getting AlfaPro's gears. Now I'm set for life, hopefully, in the HVAC department.

When you do it, do the drum reiforcement bit too (it's easy and very cheap). And if you wait too long and the drum receptor cracks, and then falls into the drum, try vacuuming the piece out from the mixing box (going down the big center vent with the drum indexed) - it worked for me! -----------

Subject: Steppers From AlfaPro Name: Don F. Time/Date: 16:17:46 10/11/2000 Message:

Thanks guys. Appreciate the reply and advice. Regards, Don '91 164S -----------

Subject: Air distribution drum not working Name: S J B in Australia Time/Date: 02:28:17 6/22/2000 Message:

Well I've only just had one problem fixed to come across another. Just got the car back from having a new s/hand air-con compressor fitted and now the only place I can get air is to the windshield....talk about frustrating!!

I'm aware of the all too common stepper failures that occur here, but the thing is that until last week, it was working perfectly, and silently too. Is it common for the stepper gears to give up with no warning like this or should I look for something else?? I will get around to taking the dash board off in the next few weeks, but I'd love to have some idea of what to prepare myself for.

Any ideas about what else may be causing this problem thankfully received!! S J B in Melbourne Australia. 89 164 3.0 Auto. --------------

Subject: Air distribution drum Name: Stuart Thomson Time/Date: 23:44:44 6/22/2000 Message:

To check whether the drum is rotating freely (i.e. the stepper is no longer connected), you have to remove the instrument cluster and the fan vents from the top of the dash. This exposes the top vents, should look like an infinity symbol (8 laying on it's side). Now if you've got small hands you can feel the top of the drum by poking your hand through the vents, try moving the drum, don't push too hard though. If your hands are normal size, you'll have to use a flexible strap of some kind to see if you can move the drum.

The drum is keyed onto the shaft of the stepper motor, if it moves freely, then the keying is broken, by default it settles to the defrost position. Replacement of the drum, installing the reinforcing ring is the only solution and involves the removal of the whole dashboard. If you give Hugh Harrison a call, he told me at the last Alfa club meeting that he'd fixed one in-situ, but I don't know how he'd done it. I'm not that flexible, and the thing is stuck away pretty well, so I pulled the dash to do mine. If you do remove the dash, fix the steppers as well, you don't want to do it twice, your steppers WILL fail eventually. Regards Stuart --------------

Subject: ACC Name: Michael Smith Time/Date: 22:26:09 6/22/2000 Message:

Sudden failure of the steppers would be unlikely. As the initial setting of the Auto Climate Control is all air to the windshield from a cold start I'd suspect some electrical hitch as Del suggests. Check all the fuses and electrical connections first.

The rear stepper that controls air distribution is harder to hear as it is deeper in the dash, but the death throes of steady clicking last for months before the system quits. Also, there's a cracking problem on the drum where it connects to the stepper, I suppose that might fail suddenly, giving the symptoms you describe (Del's symptoms could be from the same cause as well) --------------

Subject: A/C Name: Del Time/Date: 23:36:00 6/22/2000 Message:

Yes, I've thought as well (also suspected by AlfaPro by e-mail); however, because of being able to get air to all the vents (except, of course, the floor vents) I said the heck with it. That's why I wondered if the drum can somehow be turned by hand to change the settings to, say, what I have. That is satisfactory, in my mind. Saves a lot of pain dash diving. --------------

Subject: Name: Del Time/Date: 13:27:32 6/22/2000 Message:

First, check all of the fuses and connections that might be remotely associated with the ventilation system before you start pulling the dash. It is possible that either a connection was not reattached, or one or more fuses have been blown. You didn't say whether or not the lights in the switches work as you push the buttons.

If the air distribution drum is not rotating, is it possible to turn it so that more vents are active? I've determined that the air distribution drum in my car is not working, at least none of the distribution buttons (lights working) have any effect when pushed, but since I get air to ALL vents except the center tunnel floor vents, I don't care. I have resisted the urge to tear into the dash to find out what is wrong. If the temp settings go south, then I get to buy the gear sets from Oz. I suggest you contact AlfaPro (www.AlfaPro.com) located in Melbourne for more advice. --------------