Noisy left footwell blower when ignition is off

Skyounet · 03-09-2015, 05:11 PM

Hi there,

Yesterday after I came back from my road trip, I heard some noise (like electrical buzzing) coming from near the clutch pedal, after I turned off the ignition. I removed the panel on the side and I realized that the noise was coming from the footwell blower (I used it today, my feet were cold

).

First thing I did was to unplug it, but as soon as I did that I heard some fan/blower starting up (I think this one was the main one).
I replugged it and the buzzing started again.

To "solve" that I had to remove 2 fuses from the engine compartment fuses box.
Engine comp. heater blower
Footweel heater blower

Now my question:
What should I do to properly fix that?

Do I have to change the footwell blower? Can it be just a bad fuse?
I don't really care about the footwell blower but what does the "engine comp. heater blower" fuse, disabled? Is that the heating system?

How is that, that the motor keeps getting power even when the ignition is off?

Shoot your ideas

PS: It's a 1986 911.

Thanks,

Skyounet · 03-10-2015, 02:36 PM

Shameful up...

SpyderMike · 06:55 PM

The footwell blowers have an inherent issue. The squirrel cage tightens up to the body and it starts rubbing against the plastic. As it gets worse, the mechanical resistance causes the electric motor to draw more current. This gets so bad that the motor can mechanically seize and the electric motor can meltdown. That was the condition mine were in when I removed them. The sound was more of a squealing though like you would expect from something spinning and rubbing against another surface.

There is a link to how to temporarily fix this, but it does require removal. I will try to find you a link for you to check out. removal is not so hard. Disconnect the electrical plug and the hoses and pull it out. If your hoses are original, then you might lose them.

SpyderMike · 03-10-2015, 03:02 PM

Here is one:

Round heater dial should create BLAST of air from heater blowers. (If not, read this)

Searching "Footwell Blower" should return much information. There is discussion about fusing these things so the meltdown in the motor won't so bad as to melt wiring.

aj88cab · aj88cab's Garage

The engine blower and foot well fans are powered from "always hot" power through the fuses in the engine compartment that you removed.

You either have a stuck/fused relay contact in the fan control module (located on the engine compartment relay panel), or the temp sensor (thermoswitch) for the auxiliary engine cooling function that operates the engine blower is bad.

If the engine blower runs for either of these reasons, the FW blowers will run also...even on the "0" setting.

The temp sensor is mounted on the oil breather housing located under the engine blower; replace the fuses, then assuming the fans run at this point, disconnect the temp sensor connector and see if the fans stop. This is done with ignition off. The connector is a round single pin connector.

If that doesn't stop the fans, you most likely have a bad control module. Hopefully it's the temp sensor.

SpyderMike · 03-10-2015, 07:05 PM

Sorry , I thought you were questioning the noise of the blower. Here is an interesting thread on the heat controller in the engine compartment:

Carrera - Removing Engine Compartment Heater Blower

Skyounet · 03-11-2015, 05:24 PM

Quote:

Originally Posted by aj88cab

If the engine blower runs for either of these reasons, the FW blowers will run also...even on the "0" setting.

But only one of the blower if active. The right one is completely off.

Could it be just a bad left blower that for any reason is vibrating? If I was just replacing it, would it fix the problem?

Quote:

The temp sensor is mounted on the oil breather housing located under the engine blower; replace the fuses, then assuming the fans run at this point, disconnect the temp sensor connector and see if the fans stop. This is done with ignition off. The connector is a round single pin connector.

The fan is not running per se (I don't get any air), it's just making a weird noise.

Thanks,

aj88cab · aj88cab's Garage

You initial post indicated the FWB & the Engine blower are running with the engine off. Whether the FWB is running slow or seized up is not as important as confirming that there is power to the fans with the engine off. I assume that if they are making noise there is power to the fans. You can confirm with a meter if you have one.

The right FWB may be bad, or the inline fuse at the right FWB has blown, but that's another issue. I don't see a fuse on the left FWB, so you may not have the inline fuses.
You can test the right FWB by applying 12 volts directly to the fan. But, as SpyderMan discussed these fans seize up so it would not be a surprise if the fan has a problem.

If the heater levers are down the flapper boxes are closed so even if the fans are running there would be no air flow.

In any case a bad FWB fan is NOT going to cause power to the fans with the engine off.
If the fans are running (or running slow & making noise) with the car off you have a problem with the power and control circuits.

First try the above test of disconnecting the temp switch connector.
If the fans continue to run (or continue making noise) with that disconnected, you have a bad controller.

You may ultimately need to replace or repair one or both of the FWBs, but first determine the cause of you initial problem.

Skyounet · 03-11-2015, 06:54 PM

Quote:

Originally Posted by aj88cab

You initial post indicated the FWB & the Engine blower are running with the engine off. Whether the FWB is running slow or seized up is not as important as confirming that there is power to the fans with the engine off. I assume that if they are making noise there is power to the fans. You can confirm with a meter if you have one.

Sorry my first post was maybe confusing.

Basically I turned off the ignition and I heard some kind of buzzing sound coming from the left FWB. There were no air coming out of it or anything.
The right FWB is still working fine when the lever are up (when it's down they're off).
The left FWB also blows normally when the lever are up and don't blow at all (but buzz) when lever is down (ignition on or off).

The noise is really like an electrical buzzing (it's hard to describe).

When I unplugged the blower, I heard some kind a fan starting up and that I'm not sure what it was.

I'll try reconnecting the fuses and disconnecting the temp switch connector.
Dumb question: Do I just pull it to disconnect?

Thanks again,

aj88cab · aj88cab's Garage

This is the temp switch. It is not exactly under the engine blower fan as I mentioned earlier. Picture is with intake removed, but you should be able to reach back there and pull the connector off.