BlackCab

I've been looking on the internet and in Rennlist archives, but I'm having trouble finding out what the fan behind the dash is and what can go wrong with it. Recently, this fan has been running nonstop in my car even if you turn the car off and remove the key and have the CCU turned off.
The only way I was able to stop it from running is to remove Fuse #1. I know it must be related to the A/C system somehow, but does anyone have any ideas as to what the problem might be?
BTW, the A/C works fine. I'm just worried that the battery will die if this fan runs incessantly. Plus it's loud.
Any ideas are greatly appreciated

adewatson

There is a fan which is linked to the heating system behind the dash and just to the right of the heater controls(RHD). It is normal for this fan to run after the ignition is turned off for up to 20 minutes.

The fan's purpose is to draw airflow over the cabin temperature sensor so that the system gets a better idea of the temp. inside the car.

These fans run all the time the engine is running and deteriorate over time to develop an irritating buzz.

I would check to see that it shuts down after say 20 mins if not there could be a problem.

I seem to remember a fix on one of the 964 websites using a new motor from Maplin (electronic components retailer)

May be worth a call to your OPC to find a part number.

Regards

Adrian

Adrian

Dear Blackcab,
The fan will run for up to 20 minutes. If it continues beyond this time then it will flatten your battery. Unfortunately this is a fault in the control unit and it requires repair. However for the short term you can remove the fan assembly from the control unit. This has been done as an experiment and it has no impact on the system what so ever. It has been done since as a temporary fix. If you only drive in summer and store the 964 in winter it can be put off until then. If you drive all year round then maybe when some other major work is required.
The control units are fixable and it is much cheaper and far less of a hassle than trying to replace the control unit.
All the part numbers and instructions are found in my book on the 964.
Ciao,
Adrian
964C4

BlackCab

Thanks so much. Yeah, the longest I've gone was for an hour before I just took the fuse out--so it shows no sign of switching off. I will check the book and look into fixing the control unit.
Thanks again...greatly appreciated responses...

John Boggiano

I can't believe I am too lazy to open Adrian's book, which is in my bookshelf not more than four steps away from where I am sat!

However, I think I am right in saying that the electrical supply to the fan plugs in to the back of the control unit so, if you get a feel for where that is, you could just unplug it as required, for now.

(In my defence, I have just finished installing some new half-height doors around a shower cubicle and have just slumped into my computer seat!)

remjr195611

Can someone tell me where I can actually source the Inside Cabin Sensor. While troubleshooting my CCU I destroyed the thermistor and need to replace. I own an 89 964 C4

For those who may not know, I'm talking about the Thermistor thats sits right behind the vent on the front of the CCU. Air is ciculated over thus changing it's resitance value which in turn then regulates the inside cabiin temperature via CCU output to the mixing chamber servo motors. Being the part is inside the Hella CCU unit, I am having a problem sourcing the actual thermistor or and equivalent.

ziu

It´s a regular NTC resistor 10kOhm (25° C) B=3977k
find out more her:
http://www.conrad.de/ce/de/product/5...euseart-Epoxyd

Ithink yo´ll find it in good sorted Electronic stores!
Good Luck!