by Brad Anesi
Today, we'll cover the replacement of the Heater/Air Conditioner Stepper Motors, a common failure item on ‘91 - ‘93 164s. I am convinced that no single item has scared more new buyers away from the Alfa 164 than the maze of buttons which control the heating, ventilation, and air conditioning of this car. I say this not because it is failure prone (it is, and we'll get to that in a minute), but because of the sheer quantity of identical buttons which make up the control unit. Inevitably, the first thing somebody says when getting into my car for the first time is, "Is this an airplane or a car?". In reality, once operation of the controls has been mastered, it is quite easy to operate and maintain a comfortable cabin temperature. Electrically, the system operates very reliably - unfortunately however, there is a weak link in the electro-mechanical operations.
Located behind the dashboard are two Bosch stepper motors; one controls the temperature, the other controls the air distribution drum which directs air output to the various ventilation outlets. In very atypical Bosch fashion, the internal gears of these motors are made of a plastic material which is prone to wear and breakage. The typical symptom of a motor which is at or near failure is a clicking noise coming from the center of the dash area. As the motor gets to a more advanced state of failure, the system will become somewhat inoperable and may blow air from only one vent and/or at the wrong temperature. Somewhat of a saving grace to this situation is the typical amount of time which can elapse between initial indication of failure and actual failure of the motor. On my 164, I put an additional 5000 miles on the car after hearing the initial, occasional clicking noise. By the time I got to the job some eight months later, one of the motors had just failed completely, and air would only flow through the defroster outlets. Remember, "your mileage may vary," and nobody enjoys hot air blowing in July!
Initially I had planned on this article covering the entire process of the stepper motor replacement. Unfortunately however, Rex said we couldn't dedicate the entire issue to this topic, and it was decided that I would focus on adding insight from my installation experience to the ARDONA video and technical bulletin which thoroughly covers this job. Having said that, the first thing you'll want to do is acquire said video (part# 608-97496), and technical bulletins number 80.93.02 and 80.94.01. The video should be available from any of the remaining Alfa parts dealers for about $20; the tech' bulletins are best obtained by getting the Alfa 164 CD-ROM from CarDisc International (highly recommended, by the way). If you have trouble locating either of these, check with your local chapter librarian or get in touch with me (banesi@novell.com).
The initial "factory recommended" method for replacing the stepper motors involved removal of the entire dashboard - a process which took about 18 hours to complete. Since many of the initial replacements were done under warranty, ARDONA was extremely motivated to find a less labor intensive solution. It was thus determined that by removing most of the bolts which hold the dash in place and pulling it away from the firewall, adequate access could be provided to remove and replace the stepper motor assembly. An experienced mechanic can probably do the entire job in four hours. I took about eight hours, with several visits back and forth to the queued-up VCR.
Let's start by making sure we have the necessary tools to do this job. In the video it clearly shows how to fabricate a few specialized tools from Craftsman parts that you will need to get access to some of the more difficult screws. Alternatively, ARDONA now sells these tools as part #'s 18221132 and 18221133 (both are required), which appear to be even better suited to the task. I was fortunate enough to find a friend (thanks Tim Clackett), who loaned me his home-made tools. Either way you go, these are required to complete the job, along with the following general purpose tools:
long (12"+) Phillips #2 tip screwdriver (magnetic tip is very helpful) Phillips #1 tip screwdriver 13mm open-end box wrench 10mm box wrench 6mm allen wrench or socket Needle-nose pliers Wire Cutters Pick set (Snap-on Tools #ASA204A or equivalent)
Next, you'll need to make sure you've got the appropriate replacement parts. There are three:
60610100 Stepper motor assembly (around $250-) 60897530 Reinforcing ring ($1) 60805430 Circlip (25 cents) 60801430 HVAC Filter (optional, about $35)
From here forward, I will follow along with tech' bulletin #80.93.02 and reference some of the 40 disassembly and 34 re-assembly steps. I'll only make comments where additional info is helpful, but every single step must be completed in the listed order for the job to be completed properly. Admittedly, this won't make for terribly interesting reading for most of you, but it will keep the overall length of the article manageable.
Before beginning the re-assembly it is important that the reinforcing ring is placed around the distribution drum shaft as specified in tech' bulletin 80.94.01. This enhancement was specified after the video and initial tech' bulletin was issued, and it will ensure that the integrity of the drum shaft is maintained. The ring easily slips over the shaft and the notches guide it into the proper location. To ensure the ring is properly positioned, purposely put it on wrong and twist it until it slips into place. Then give it an extra push to make sure it is fully seated. The ring does extend a bit beyond the end of the shaft.
The remaining re-assembly steps are quite straightforward as long as you don't get too anxious as the project nears completion. It is important that everything is properly tightened or you may end up with a noisy dashboard when all is finished.
At the end of the video, Dave Rogers makes mention of the very early production 1991 models which have a slightly different bracing structure, and are identified by two bolts in the glovebox. It goes on to describe a different procedure for removing the defroster vent on these cars. My car is a 3/90 production vehicle, the 199th 164 brought into the United States. It has the two bolts in the glove box, but the two bolts attach to only a nut on the other side of the glovebox, performing no function whatsoever. My friend Tim Clackett, with a 5/90 build car, had exactly the same situation. I've also spoken with one of the top Alfa mechanics in the northeast who has yet to see a car that actually had the different bracing. Dave Rogers has assured me that some of these cars do exist, but they are very limited in numbers. If you find that your car does have the two bolts in the glovebox but your VIN is greater than xxxxx199, I'd suggest leaving the bolts in place and see if any resistance is encountered when you go to pull the dash away from the firewall. I suspect you'll find none, and you can proceed ahead without the alternate procedure.
I've now had my new stepper motor assembly installed for two months and it has performed flawlessly and quietly. Aside from one occasional creaking noise emanating from the center console area (which seems to be gradually disappearing as everything settles into place), I'm very happy with how the project turned out. Overall, it was not a terribly difficult job with the video and bulletin to methodically guide me, but it is rather time consuming.
I hope that by the next time I have to do this job, Alfa and Bosch will have figured out how to build more reliable stepper motors (I'm not terribly optimistic however). In the mean time, my "preservation strategy" for the new motors involves three steps:
Now that we've completed some of the more mundane maintenance items, next issue we'll start to explore some "go faster" parts for the 164 - stay tuned.
My thanks go out to Dave Rogers, Fred DiMatteo, Joel Hailey, and Tim Clackett for their assistance with this article.