964 climate control servo issue?

[bigchillcar]

whaddaya know...another mystery on the 'new ride'.. i'm thinking there's a problem with the servo for the center vents. driving along, even though it's cold outside, i'm in the sun and getting a little warm. i dial the temp knob all the way down to the 'blue'. i get cool outside air thru my side vents, while my dash center vents continue to blow hot. i'm right aren't i..? servo..
ryan

[LeRoux Strydom]

lol, maybe you screwed up more than the airbag unit when you did the radio swap...

Seriously, the ccu is right next to the radio. I would unplug everything back there, maybe clean out the little fan at the rear (which is known to cause problems when all the dust gums it up), refit and try again. That UK site also has good info on how to test the servos. It not difficult to do, trouble comes when you have to replace the leaky a/c evaporator. Ask me how I know...

[LeRoux Strydom]

btw, good luck with finding all the usual 964 gremlins. You'll learn a lot about the car. The upside is that the 964 is such a rewarding driver's car.

[bigchillcar]

agreed, leroux..the car's an absolute blast..and agreed - electrical problems seem to be the achilles heel so far..lol.

i need to replace one of the fans already..has a bab bearing and you can hear it somewhere under the passenger side dashboard. it's intermittent, not really very loud, but going to drive me nuts until it's replaced. i bet it's a cheap part, but a b!tch to get to..

i'll be sure to check the back of the ccu, thanks. btw, when i pulled out my clock/control unit the other day, i found two plugs in the space behind it not connected to anything..don't really think i pulled these though. one is two melded purple wires, the other a yellow/red meld. any ide what they're meant to pug into? they feed into that typical rough-textured 'conduit'..
ryan

[LeRoux Strydom]

that screeching noise near the passenger side is actually the little fan at the back of the ccu! Easy to remove, clean out, lubricate, refit and your good to go.

I'll need to pull out my own car's clock to see which other connectors you talk about. Not going to do that now, its late & raining outside, and the garage is detached...

[bigchillcar]

thanks, leroux! how do you get to the fan..through the trunk area or up underneath the dash. you need to remove the ccu?

[LeRoux Strydom]

you need to make the tool (bent piece of wire) to insert into the 4 holes on the front of the ccu, then remove it like the radio. Look on the uk site for instructions. On the bench, the little fan is very easy to clean & lube.

[bigchillcar]

bent piece of wire, leroux? like a coat hanger? i've seen the four holes in front of the ccu where the knobs, etc. are...but how would a wire allow one to pull the unit out? i would have thought it was held in by special screws requiring the odd bit..no? it sounds like the fan is under the passenger side dash though. you're certain there's not one underneath there? i checked the john's u.k. site and only see his article for repairing the servos per se..
ryan

[Don Plumley]

The wire in the holes release catches on both sides of the ccu - it pops out.

[smith737]

I've had a similar problem with my 964, the r/h air con fan was squealing. The 964 has 2 a/c fans under the dash (accessed from the trunk behind the fuel tank), a left hand and a right hand.
And that UK site has some great tech info (www.porsche964.co.uk).
Oh and the bearing just let go on that fan and now its a new one from germany, cost $600 aussie ($500usd).

[bigchillcar]

smith..that's what the p.o. told me..that it was a fan accessed through the trunk, like you mention. $500 u.s. for the fan?? holy cow! lerouuuuuux! can this thing be rebuilt? hell, anything can be rebuilt, right???
ryan

[LeRoux Strydom]

Let's not get confused.

There is a small fan mounted on the back of the ccu. This often becomes gummed up by dust & dirt, and can make a screeching noise. It certainly did so intermittently on my car, sounding like it came from the passenger side. You can clean out this fan easily.

Then there are two main ventilation fans on either side of the airbox in the front trunk. Access to these fans is much more difficult as you have to remove and open up the airbox, not a trivial exercise.

You have be sure about the source of the screeching noise. If you hear it sitting inside the car, stick your hand underneath the ccu, feel for the little fan and stop it with your finger. If the noise disappears, you found it.

If you can hear the noise better by standing outside the car with the trunk open and the black plastic cover behind the fuel tank removed, then it may be one of the main fans.

[bigchillcar]

i should be able to reach underneath and behind the ccu and feel it? okay, i'll give that a go. the p.o. indicated that it was the fan on the passenger side and that it had to be accessed through the trunk, so i'm betting he knew what he was talking about. had it been easy, he would have done it. he said it was annoying, but he just learned to live with it. it's intermittent.

assuming it's this fan..is this a different case from the ccu fan? am i looking at replacement as the only option or does your repair/lubrication plan still apply?
ryan

[LeRoux Strydom]

If it is one of the front fans, the biggest work is actually getting it out. By the time you're that far, its easy to assess if it can be fixed or has to be replaced.

This pic shows the small fan at the rear of the ccu:



BTW, here is the link for testing the servos:
http://www.porsche964.co.uk/technical/servos.htm

A search on the rennlist 964 forum for "ccu fan repair" yields a ton of threads with good advice.

I hope its not one the front main fans.

[bigchillcar]

leroux..is it that black thing on the back of the unit that i'm seeing? i've got john's 964 u.k. link...a great resource, no doubt. i'll be sure and check out rennlists's threads..i'd forgotten to do so. i'm almost 100% certain it's the front passenger main though. is it repairable do you know..or must be replaced?

[LeRoux Strydom]

Yes, its the black box on the rear of the ccu. You can easily feel it with your hand by sticking it underneath the dash and feeling for the ccu's behind (hehe). Try it when the car is running and you can hear the screech, then try and stop the fan with your finger. Its not a very strong fan.

I am sure the front fans are repairable, but can't remember what bearings they had from the time mine was out to replace the a/c evaporator.