FredR

Another interesting suggestion- a few weeks ago I felt my a/c compressor was making a bit more noise than it should when listened to at idle from the front of the car- I took it to my friend at the main dealers for an opinion and he felt the noise was nothing more than might be expected for a machine covering such mileage. If my a/c craps out in a couple of weeks we will know what it was! Not sure if a sudden jarr would induce the squeal but interesting nonetheless.

Thanks

Fred

auzivision

HVAC blower motors are also know to make intermediate high pitch squeals.

davek9

Fred, Last night I looked at the wiring on the console I'm reinstalling and on the motor I just cleaned before re-installing it.
The motor has two wires White w/ Red and a brown, it unplugs directly at the base of the motor (if you can get to it).
The same two wires go to a 4 pin that has two yellow wires for the inside temp sensor and the two for the motor, that connector is behind the HVAC, and that may also be a good spot to disco the motor, however the sensor needs to stay connected.
I'll post up some pics later today when I get them off my phone

Dave

FredR

Sir,

You are a star!

FredR

Dave,

Took the 928 for a nice ride this afternoon. Whilst out the issue took a new turn in that it started to squeal continuously. Gave the dash a thump over the top of the air intake thingy and the noise stopped. I think I can safely say I now know what the issue is!

davek9

Hi Fred, here are some pic's of the motor (removed from the housing and the 4 wire and also the 2 wire (orange) that go to the center vent micro switch.
They are both hanging down together in the center and attached via hold-down to the HVAC unit, so you should find them in the same place.

Hope that helps, and yes the center con will need to be removed to replace that motor



Also I used on of Nat's printed vent tops in my console and it worked GREAT!

Dave K

FredR

Dave,

Any idea how many thumps the dash panel can handle before it deforms?

Many thanks for the pics and the input. Sooner or later I am going to have to pull the dash and have a crack at the HVAC issues- that or rip the job lot out and put a fixed switch on the blower and run the a/c with an on/off switch!

FredR

Well the problem has gone from an occasional squeal when I go over a bump to a continuous squeal when I go over a bump and no amount of thumping the dash panel will stop it- urrgh!

Absolutely no doubt what the cause of the problem is- well done Dave! I would never have found that one I suspect especially as I did not know there was a motor in there. Tomorrow all being well I will pull the side panel and see if I can find connector 31 with the two yellow cores, a red/white and a brown cable. The red/white is the power supply to the motor and the brown the earth. If I can disconnect the red/white [or the earth] that should silence the thing. As I do not use the temperature controller feature that should not cause any issues or so I would think].

FredR

Actually I have had terrified passengers, one a very nervous individual who crapped himself when I started the engine and he heard the rort of the exhaust and the car was stil in "park". Another good friend, a local chap who was sat in the passenger seat was quite impressed when I accelerated hard past several cars to ensure I got a clear run at the exit ramp we were approaching. As I exited the highway he made the mistake of asking me if it stopped as well as it accelerated. I briefly looked at him with an evil grin, took a squint in the rear view and applied the anchors. To my horror his entire body was lifted out of the seat, he frantically tried to brace himself against the dash panel and roof when he was clear out of the seat. Turned out he had the seat belt over his chest but for some weird reason did not latch it and was holding the clip in his hand- he never did that again when riding with me. I also had the owner of the local franchise in the car with me once. He was the original owner of my current 928 GTS and asked me to test drive the poor thing. At the time I was not impressed with how it performed and invited him to have a ride in my late 90 S4. After briefly going airborne he seemed a bit pale so I took it easy after that!

Some time later, being somewhat concerned about what I perceived to be a lack of performance, my good friend the local service manager took the car for a test drive with me in the passenger seat- that convinced me there was nothing wrong with the car! It is one thing when you are in control of something you are used to but quite another when sat in the passenger seat watching the world hurling towards you at warp speed! It really was an unreal experience- makes me wonder if I am the only one like that or whether others experience the same sensation. Either way I take it steady with passengers in the car unless they ask to "give it some welly".

FredR

Today I removed the passenger side access panel to see if I could locate the power supply to the suspect motor. I was hoping to find connector 31 but could not trace it. I managed to locate connector 29 and pin 4 of this connector is the cable that forms pin 2 of connector 31 but that cable disappears behind the bulkhead as it presumably approaches connector 31 but I could not get my hands on this- urgh! The only other thing I can think of is to trace the earth connection for the motor. There are some 6 cables going to earth at the same point- appreciate if anyone can give me a clue as to where this earth point is located. That or I will have to trace back from a known point such as the earth cable from the solenoid valve array for the actuators.

FredR

I think I cracked the basic problem this afternoon. I decided to remove the HVAC control unit just to see what I could see. Lo and behold the connector I could not locate was sandwiched between the frame and the unit. Followed the cables and found the connector on the base of the motor so disconnected the fan motor. Hopefully that will cure the squeal. I am assuming I do not really need that fan to work - hopefully it will not toast the temperature sensor. I do not use the control that selects cabin temperature- during the hot season I need maximum cooling and if it gets a bit chilly, as it can, I simply turn down the blower a notch.