adidas

My 91 964 fans are always on. I always feel air coming from the vents on the dash. With the igntion switch on and the temp **** on the dash mounted climate control unit turned to the hot setting, the rear engine heater fan comes on. When the temperature **** is turned to the cold setting I can hear the front fan on. Both times the fan speed **** on the ccu is in the OFF position. I always feel air from the dash vents even with the fan speed **** off. Any ideas? Thanks

adidas

Anyone?

s4magman

Sounds like the CCU needs a rebuild. You'll notice that the fans will run even with the CCU removed from the dash. There are a few Porsche DME repair shops out there (google it). I just had Specialized ECU Repair (no affiliation) rebuild my CCU.

jody stowitts

Is this a recent development? Its my understanding that the rear blower is ALWAYS on (low speed) to keep a certain amount of FRESH air coming into the interior. Are you certain that both front fans are actually ON, and not just feeling the air flow from the rear fan? If so, you might check relay(s).

jody stowitts

P.S., regarding my earlier posting: page 64 of my owner's manual states regarding the fan speed rotary switch that "at the 0 setting the fan runs at minimal speed". Hope you've got no problem at all. Cheers.

ToreB

The rear(AUX) fan should start when you turn up the temperature setting. That fan helps pushing the heated air to the front. This is normal behaviour.
Are you sure it's the front blower fan you hear, and not the small CCU fan that has started making noises? That's quite common. Have a look here for details on the CCU and other HVAC issues:
www.ccu.tore.bergvill.com

Cheers,
Tore