JBL930

What car is this on? The BTR? I've never seen an extra "de-mist" fan on a stock 930, was it an optional extra?

bill930p

Yes, it's on the BTR.

That's what I'm trying to figure out.

fullquack

The dash switch activates both fans at the same time, just pick what ever crappy speed you want. The fans are marginal at best & only really help when sitting at a stop light, as long as you don't breath or your coat is not wet!

My car also came with a heated rear window, with that activation switch on the dash above the radio, right next to the fog light switch & cig. lighter. Maybe the fans were part of a "factory defrost" package??? Who knows???

When I bought my car only the passenger side worked, as the drivers side was melted into a big glob of f#%@, amasing the car had not caught fire!
At $125.00 a crack to replace vs. how marginal they work. I would not have replaced the dead one, instead I would have simply removed them both & sealed off the duct tubes.

F.Y.I. all my wiring is stock, and everything worked, including the automatic climate control which WAS linked to the heater & A/C. The 2 fans were never linked to that system.

My .02 worth.
Mark

JGMACHINE

Have one on my 85. Its for fan speed for heat/defrost.

bill930p

Thanks guys. I took the **** off, to see if the dash was cut into, or if it was manufactured this way. It is definitely factory. So it seems like it is for the heat.

willtel

Has anyone tried to replace the footwell blowers with anything better? My car is a daily driver and defrost is a nice luxury to have. It seems like I could put a small ducted type fan inside the heater tube but I'm not sure if it could take the heat.

For what it is worth my '87 has no separate switch for the footwell blowers. I believe the heater control box between the seats handles it all automatically. Some time in the mid '80s in line fuses were added to the footwell blowers to prevent fires. I think several 911s met their untimely end because of those fans catching fire.

JDHertz11

Shoots my idea to ****.....

fullquack

I put a fuse inline with mine when I replaced the melted drivers side unit, so I should not go up in smoke now!
The biggest problem I see with attempting to "up-grade" the blowers, is that for most of the time (low engine rpm) these blowers are actually trying to suck hot air from the engine. Then when the engine rpm is up, you don't need the blowers. So the base problem is much like the "automatic climate control", it simply does not work well with a constantly varing air supply.
This is one place where the h2o cooled Porsches have a luxury advantage.

I just keep my car in a heated garage, and then simply drive fast at high rpm to keep the hot air moving!!

Mark

A930Rocket

I was wondering about adding a switch to my 87. The auto heat has been removed and I just have the laever now. I still can't figure out the dash controls after 12 years....

WERK-I

+1 on inline fusing the motors. I replaced both of mine and inspected what was left of them. The commutators were melted to the brush mechanism. A fire waiting to happen!

Every time I look at the comfort controls in the 930, I am so very grateful they didn't do the HVAC in my house!

kens911

My 88 doesnt have the switch. it has the auto controls for heat. the drivers side foot well is the only one that works. it's real easy to tell when it's running it blows smoke from the oil dripping on the headers out the defroster duct. lol...

nathanUK '81 930 G50

You know, actually the heating system is excellent providing it's working as the good Dr. intended and you understand how to use it.

To defrost, put all the levers to the right except the top two (the two that are side by side). Finally put the **** between the seats on full.
The top two side by side levers are cold air only, the first one can shut off the cold air altogther and the second can boost it via the fan in the luggage compartment if you so wish.
If you find you are too hot while trying to defog the windscreen you can use the top two levers to mix some cold air on to the screen too.
Neither of my cars have a/c so I can't comment if you can use that to help defog too.

willtel

Close. If you have the top lever all the way to the left blocking fresh air flow then the center lever does nothing. Once you open the fresh air vent the middle lever can be used move that air through the dash vents or it can be directed through the defroster ducts. The bottom **** is red because it only directs heated air, either through the dash vents or through the defrost ducts. Confused yet?

notthd

Hell yeah- I have owned 911/930 for years and never did take the time to learn EXACTLY how the hell the heat and AC worked- OK after awhile I figured out how the AC worked or er didn't work , but the heat I gave up on since our weather never gets that bad- If so I am in something else.... Great to know- I guess one day I eventually would RFM.

My 85 ROW does have this switch. I think it turns on the celing fan in my neighbors house since I cannot hear anything unless it's on 3- Cheers, Mike

911rudy

My car came with inline fuses that look like the PO installed them. They are newer than the OEM electrical type fuses.