Engine Mounted Heater Blower Motor

[earossi]

It's pretty common to loose the bearings in the heater blower motor that is mounted on the engine in the 82-89 911's. Mine was noisy when I bought the car, and I just got around to replacing it.

When I turn the key in the ignition, the fan comes on, and I have not been able to determine how to deactivate this fan unless I turn off the ignition. Since it is meant as a boost fan for the heater, you should be able to shut it off when the heater is not needed. The wiring diagram in my Bentley manual is of little help since it just shows the wiring going into the climate control box.

So, my dumb question is: is this fan supposed to stay on at all times; and if not, how do I determine what is not working correctly?

TIA

[84toy]

Each red lever between the seat has an individual contacts and the fan will come on when either lever is pulled. On mine the fan will come on when the lever is moved about 1\8" The good part about that is that you can turn it on in traffic on a hot summer day to help cool the engine without heating the passenger compartment. I would guess that one of those contacts are closed or the relay is stuck.

[RoninLB]

Originally posted by 84toy
The good part about that is that you can turn it on in traffic on a hot summer day to help cool the engine without heating the passenger compartment. .

I by-passed the 2 floor sw and installed a manual sw for the rare times I was actually looking for the fan operating

[earossi]

Thanks for the two replies. Unfortunately, my 89 has the fully automatic climate control system, so they have deleted the old red stalks that allowed you to control either side flapper valve. Instead, all I have is the single rotary switch and the system utilizes an electrical solenoid to regulate temperature.

Perhaps someone else with the fully automatic set up could comment?

Thanks.

[Erakad]

Bentley's has a calibration procedure....perhaps it needs calibration??

[Wavey]

According to the Bentley manual, the fan is also activated when the engine compartment temperature reaches 260 degrees, the vehicle is stationary and the ignition is on. It says that it is switched by a temperature switch in the crankcase vent cover at the rear of the engine. Could be a bad switch if everything else checks out.

You could just disconnect the fan at the wiring harness connector, but this will also cut power to the footwell blowers.

If you want to replace the motor, see:

Carrera replacement heater blower (long)

[earossi]

lWavey,

Thanks for the reply. Unfortunately, I had already purchased and installed a new blower assembly. Got it for about $180 from Vertex. I did see you Grainger note, but AFTER I replaced my motor.

Incidentally, I noticed from your signature that you have done pretty much what I am thinking of doing.........Steve Wong Chip, Euro/pre muffler and sport exhaust. Can you comment on which of those made the biggest difference and "if you had it to do over again", what would you change? Also, noticed that you had installed a Broadfoot intake. What does that buy you and how much did it cost you for the hardware?

Thanks.

[Wavey]

Hi Ernie -

I supose the chip made the biggest improvement, but the exhaust sure sounds sweet too, so you have to factor that in. I wouldn't change anything, other than possibly going with the dual-outlet Dansk Sport, but I'd have to hear one first.

RE: the Broadfoot intake, it's a round machined aluminum plate that bolts on where the air box did, has a radiussed edge at the intake hole, and used a large cone K&N filter. Don't know how much power it provides, but it was the first thing I did and I felt a difference. I like the sound a lot and it really opens up the access to the right side of the engine bay. I won't start another debate about K&Ns, but I really like them and have never seen any real evidence that they aren't at least as effective as the stock filter. I think it was $80 from Broadfoot.