how do stepper motors know where to "park"?? HELP

91RecaroS · #1 (**permalink**) 10-01-2005, 03:00 PM

I just changed my temp control stepper gears. I didnt opt for the metal gear set...I installed a used stepper gearbox.

What a royal PITA that was, it was BRUTAL. Getting the stepper back in was very time consuming. I went in through inspection hatch in glove box.

I have full range and no funny noises from stepper, everything seems ok except the motors dont seem to be "parking" correctly. When I turn the climate control to off the system parks in full cold position as normal but they seem to want to keep going. First they stop at proper spot but then they twitch about once every second trying to extend even more. This has nothing to do with the gearbox as the motor does this even when detached from the gearbox. Is there something that tells the mootrs they have reached full extension? I am not reconnecting wiring harness to stepper assembly as I dont want the gearbox to strip itself.

I hope this is clear. HELP!!

**Alfisto Steve** · #2 (**permalink**) 10-02-2005, 06:34 AM

That is pretty much how system works don't think you have anything wrong.

AlfaEricWashDC · #3 (**permalink**) 10-02-2005, 08:22 AM

Not really Alfisto, My experience is having changed mine using one of those CD's or video on how to... and it was like brain surgery for such a simple replacement. We had to remove the entire dash and thought Id never get it all back together correctly! One thing I do remember is after having it in place you also had to position the rotator duct counter clock wise at full posotion. You may have it off track a little.

Id like to ask if the A166 steering wheel could fit the A164. Id like to replace mine with one of those nice wood ones. Im in the us and we have no replacement parts for my car. We do have plenty of maintanence parts but not much with upgrades. I recently get a set of 18" rims and the car looks sweet. Ill post a pic soon. OH Im also new to the Alfa BB.

please advise.

91RecaroS · #4 (**permalink**) 10-02-2005, 08:41 AM

ok, maybe Im just paranoid.

Working through the inspection hatch was such a PITA, I NEVER want to do that again.

Im going to wait until I can replace heater core and recharge AC before I reconnect steppers.

91RecaroS · #5 (**permalink**) 10-02-2005, 09:10 AM

Ahhhhh, now I feel better.

Found this quote on Alfapro web site,

"When the ACC is switched off, the temperature mixing flap motor rotates the flap to full closed (i e cold position) and the recirculation motor (not one of the infamous steppers but a stepper type motor of a different design, located on the end of the AC evaporator housing in the false bulkhead area of the engine compartment) causes the recirc flap to close the outside air inlet. The temperature mixing flap motor pulses to maintain pressure on the flap to exclude any warm air flow, and depending on how many gear teeth have stripped on your particular stepper, the frequency of the ticking can vary."

So the pulsing is normal, as long as I dont hear any funny noises Im all ok.