140 Series A/C Sensor Fan
 

Does anybody know how to get to the 140 chassis air conditioner temp sensor fan. It is supposed to be somewhere in the dash. This is the fan that is ducted to the small opening in the ceiling by the interior lights and sucks in air to run it by the sensor that tells the A/C system what the inside temp is. Mine is starting to have an intermittent squeal and I wanted to try to oil the shaft of the fan motor if I could get to it. Thanks techs.

On the W140 chassis (& later cars) the fan is made on to the in-car temp sensor.
It is mounted in the dome lamp assembly.

Doc, is this the only fan on the system other than the fan that blows the air thru the vents that is located under the outside filter. I definately have a squealing fan noise (high pitched and not very loud), that does not vary by raising or lowering the fan speed or cutting the compressor on or off. It only stops when the whole a/c system is shut off completely.

I took the sensor fan out in the headliner by the interior lights and it is not squealing at all. Fastlane shows a heater fan for my car in addition to the main fan under the outside filter. Where is this fan and how does a person get to it?
Thanks.

Hi. Someone can correct me if I'm wrong, but my 1996 S500 (W140) Coupe only has one heater fan. Its available as an assembly, a motor and fan, or just then motor... so, that may be the confusion.
Phil at FASTLANE can get you just the motor... that's what's squealing... at least it was on mine. Mine squealed regardless of fan speed too.... sounded like like somebody strangling a squirrel in the dash.
Easy to get to... take out the 6 or 7 large phillips head screws that hold the air plenum (cowling) in place right in front of the windshield wipers. Once its loose, you'll have to remove a vacuum line and several sensors to get it completely free.
Once its out, the main cabin air filter is directly underneath on the passenger side. Lift out the filter and you're looking at the fan assembly. Comes right out after you remove the screws and turn it a bit. Easy job.
Hope this helps. Good luck.
KenP