low humming noise
 

hi all

i have a 1997 a8 and have lived with this low humming noise that sounds like its the blower

i notice if i turn heater temp to low it stops ?

but turn temp up the slightest its there again

its now getting on my nerves and wondered if any one has any ideas

thanks

Is it just dependent on the speed of the blower motor, or does it only do it when increasing the heat? Try leaving it on a much cooler setting and manually increasing the blower motor speed and see if it still does it.

low humming
 

hi

no its not speed sensitive its temp sensitive if i have my heat set at lowest it doesnt make the noise turn it up 1/2 a degree and it starts humming

thanks

I would say there is a problem with one of the temperature flap motors or something inside the heater duct is moving around etc. In any case, the entire dash board would have to be ripped out to have a look around in the A/C duct work. Its going to be an expensive repair if thats the case, if its a temp flap motor it won't be as bad but still expensive.

hi

ive had a look and listen under hood today and there seems to be (no idea what they are) two what look like soilenoids and one of them is making the noise

i will try get a picture and post

but thanks for sugestions

Yeah if its under the hood then it should be easy for me to identify with a pic.

humming noise
 

hi

ive put a picture in my gallery dont know if link will work but here goes

https://www.audiforums.com/forum/alb...pictureid=3059

see what you can make of that

thanks

Im not sure what that is, i never had to deal with one before. It looks like its close the fresh air duct so it might control the flap to open and close it. Did you try to remove the filter and see if the fresh air flap opens and closes correctly?

humming noise
 

hi

yes the flap works fine will have to strip down and see what i can find

thanks