JE928Sx4.

If you have obvious Magic Blower Syndrome on a car, but it happens when the fan setting is at full anyway, does that mean that something in the resistor pack or with the fan itself is messed up?
Otherwise the fan would be blowing at magic blower speed anyway. Correct?

glack

JE,

If you are having MBS, then you're having MBS. It happens no matter what setting the blower speed is at.

Good luck

Jerry 87 928S4

I took my resistor pack out at least 5 times adjusting it until it finally stopped. In the process I even bought a new one but it did the same thing.

Let me know if you want the details.

JE928Sx4.

So automatically you are never able to get full blast on the highest setting of the fan? Is this because when you have MBS and it only goes to full when the resistor gets hot and the system reacts to cool it down? Weird.

JE

JE928Sx4.

Jerry,

Yes, I want the details. But what I really want, is a fan that pumps the air out like it does temporarily when MBS kicks in.

Jerry 87 928S4

First of all, I am not an expert but I can tell you what I did.

Mine works perfectly normal on all 4 settings. Each setting is controlled by the resistor pack which contains an activation strip and 4 coiled wires. The size and diameter of the wires controls the fan speed. In my case when the car gets hot the activation strip expands and completes the connection turning the fan on Maximum by default.

I increased the gap between the activation strip and its connection. I also made sure each wire was away from the activation strip. As I mentioned I played with this many times to get the gap great enough and to ensure all 4 speeds of the fan worked.

I think you are saying that you dont get the max. speed unless the MBS kicks in. Maybe you should pull out the resistor pack and look at it but maybe the problem is also in your AC/Heater control unit. Sorry, best I can do.

ErnestSw

When my brand new 87 S4 was delivered it not only had a bad rack, but the AC blower would suddenly come on full speed for no reason. I've never heard of the MBS, but I assume this is it. I took it to my local Porsche dealer who fixed it under warranty, but I always wondered what the problem was.

Andre Roodnat

Jerry,

I've tried locating the resistorpack once, but I wasn't able to find it. On Nichols site it says: "Its' just in front of the firewall in the center, above the engine inside a plastic shroud".
It's probably my bad English or stupidity, but I really couldn't locate it. Could you please give me some pointers on location and how to remove?
I have a euro '89 S4

Thanks.


Rennlist member

Jerry 87 928S4

Attached is a picture. It is held in place by two screws that you access from the outside. However, it comes out from the inside of the plastic shroud. So, you have to place one arm ( small arm) inside the plastic shroud to hold it while you remove the screws with the other.

It would be much easier with 2 people and I dont know where it goes if you drop it

What you see in the picture is a black plug ( just past the white strip tie) - it is inside the shroud and attached to the other side of this plug.



Here is a link to the resistor pack sold at 928intl

http://www.mailordercentral.com/928i...em=84&mitem=92

Andre Roodnat

Thanks a lot Jerry!
I'll try and pry it out this weekend. With your picture, it will be findable.

JE928Sx4.

Thanks Jerry. Maybe a coil in the resistor pack is bad. I have a spare HVAC unit with a resistor pack in it. Looks like I'll just have to mess around with it some.

Best Regards,

Andre Roodnat

I took the resistorpack out this weekend. The resistors turned out to be OK. I had a look at the electrical drawing and saw that the resistorpack should contain a thermal overload. After some searching I found it. It is located on the backside of a small bridge, under the resistors. You have to take off the metall casing first. It is a little bimetallic contact. The contactpoints were dirty. I cleaned them with some P400 sandpaper and some contactspray. Screwed the pack back up again and voila.

JE928Sx4.

I pulled mine out this weekend. Messed with it. Even manually set off MBS. The that stopped working. I still have what appears to be 4 different fan speeds, but now don't have the "blows your hair back" power. Defrost still works. Wally suggested looking at the flaps to see that the system is able to move the air. That is next weekends project.

Bernie

Just so you know,

If you do drop the resistor pack, it doesn't go anywhere. I think it just slips down in front of the AC condenser....

I dropped mine when I did it and I was freaking out until I looked in and saw it right there. Oh! that's easy.

Make sure you don't lose your washers from the screws though...

JG928S4

Blower intermitent to full setting randomly. Pulled the plug. Had 13 year old daughter w/long skinny arms hold resistor after putting arm inside shroud housing on passenger side. removed resistor pack. Cleaned all contacts for plug, male and female, cleaned contacts for bimetalic heat strip and adjusted gap, re -installed and seems to be working perfect. 15 minute job.