AC/ Ventilation system not working
 

HI all, I have a 1991 964 C2 Convertible. The ventilation systems seems to have a short somewhere. right now the fuse is taken out so my ventilation and AC is not working. If I leave the fuse on my battery drains and I have to jump it. I came across the issue by trial and error so now it's been 5 days and the battery is still good after removing the fuse. Any ideas or hints that you can provide will be greatly appreciated. Thanks in advance. Let me know if you need more information.

A common problem is the driver transistor for the sampling fan fails and leaves the sampling fan running permanently - hence the flat battery. The transistor is only a few cents from a decent electronics store. There are some threads on the issue on Rennlist.

The HVAC system on the 964 is pretty complex with 3 blowers, the sampler fan, 5 servo motors and a computer (the CCU) to contend with. My suggestion above is merely an initial suggestion but worth checking nevertheless.

Regards

Dave