heater and fan problems
10-30-2002, 01:32 PM
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heater and fan problems
I have a 94 993 and i cant seem to get the heater to blow out the windscreen vents only the centre vents works, also both the oil cooler fan and the rear fans run full time the rear fan in the engine compartment runs for about 20mins
after the car is switched off.
It might be the ccu?
any help how to fix this problem would be really
great.
after the car is switched off.
It might be the ccu?
any help how to fix this problem would be really
great.
10-30-2002, 10:55 PM
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>I have a 94 993 and i cant seem to get the heater to blow out the windscreen vents only the centre vents works
It's possible the defrost flap servo is seized, which will (of course) prevent air from flowing to the windscreen vents.
Here's a great thread on troubleshooting the HVAC system:
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=4&t=001405" target="_blank">HVAC</a>
In addition, you can test the servo motors by applying 12V at pins #4 (+) and 5 (-).
>also both the oil cooler fan and the rear fans run full time the rear fan in the engine compartment runs for about 20mins
If the rear blower runs for awhile after shutting off a hot engine, it's normal. Also, the rear blower provides heated air to the cabin, so it's normal for it to run when you've requested heat (> 21C or so). Finally, it will run with the engine on, to help cool a hot engine.
Does the oil cooler fan run even with the ignition off, or only with the ignition on? If it runs continuously with the ignition on, the previous owner may have disconnected the oil cooler temp. sensor, behind the right-front headlight.
All this said, you may also have the same problem Buck had = $CCU$:
<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=3&t=004499&p=" target="_blank">Rear, Oil Cooler & Condenser Blowers, A/C Compressor Fixed</a>
You do seem to have an awful lot of CCU related problems. Hmmmm ....
Best of luck!
It's possible the defrost flap servo is seized, which will (of course) prevent air from flowing to the windscreen vents.
Here's a great thread on troubleshooting the HVAC system:
<a href="http://forums.rennlist.com/forums/ultimatebb.php?ubb=get_topic&f=4&t=001405" target="_blank">HVAC</a>
In addition, you can test the servo motors by applying 12V at pins #4 (+) and 5 (-).
>also both the oil cooler fan and the rear fans run full time the rear fan in the engine compartment runs for about 20mins
If the rear blower runs for awhile after shutting off a hot engine, it's normal. Also, the rear blower provides heated air to the cabin, so it's normal for it to run when you've requested heat (> 21C or so). Finally, it will run with the engine on, to help cool a hot engine.
Does the oil cooler fan run even with the ignition off, or only with the ignition on? If it runs continuously with the ignition on, the previous owner may have disconnected the oil cooler temp. sensor, behind the right-front headlight.
All this said, you may also have the same problem Buck had = $CCU$:
<a href="http://forums.rennlist.com/cgi-bin/rennforums/ultimatebb.cgi?ubb=get_topic&f=3&t=004499&p=" target="_blank">Rear, Oil Cooler & Condenser Blowers, A/C Compressor Fixed</a>
You do seem to have an awful lot of CCU related problems. Hmmmm ....
Best of luck!
10-31-2002, 02:25 PM
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>In addition, you can test the servo motors by applying 12V at pins #4 (+) and 5 (-).
One additional thought. Swapping the polarity should cause the motor to rotate in the opposite direction.
One additional thought. Swapping the polarity should cause the motor to rotate in the opposite direction.