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Old 08-26-2017, 09:03 PM   #1
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Climate control fan not working

Non a/c 986 2001
Air/heater blower not working .fuses all ok. Relays appear ok. But if I jump the relay posts the air/heater switch works as it should to turn the blower on and off and increases blower speed as it should.
So fan is working but switch not activating the relay to turn it on .

Help please.

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Old 08-26-2017, 09:30 PM   #2
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How does a relay "appear ok"?

Swap the relay for a known good one, preferably new.
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Old 08-27-2017, 08:55 AM   #3
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relays tested

all relays tested and 2 new ones also tried and tested but no joy.
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Old 08-27-2017, 09:06 AM   #4
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When the relay socket at pins 87 and 30 are jumped - the air blower fan switch can be turned on and operated as it should. ????? with the relay in place the switch/control does nothing.
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Old 08-27-2017, 09:07 AM   #5
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Quote:
Originally Posted by Skullbiker View Post
Non a/c 986 2001
. But if I jump the relay posts the air/heater switch works as it should to turn the blower on and off and increases blower speed as it should.
Please further describe how you are doing this.
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Old 08-27-2017, 09:08 AM   #6
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Switch bad?
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Old 08-27-2017, 11:44 AM   #7
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Paul.
I have done "out of socket" tests on the relay and several others which showed them to be good.
tested the relay socket with test light .light illuminated in socket for pin 30.
With the relay back in the socket . when the air/heater blower switch is turned , across all settings, Nothing.
If I remove the relay and jump the sockets 87 and 30 the fan works - operated by the switch on the console.
What could be causing the console switch to be non operative when the relay is back in place ?

is it possible to just continue with the switch operative with the relay jumped or is this a no no ?
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Old 08-27-2017, 12:35 PM   #8
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There has to be more in this circuit than the switch, fan and relay. If that was all that is involved, the fan would run continuously when 30 and 87 are jumpered regardless of the position of the switch.

Time to dig out a wiring diagram and to check for climate control error codes.
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1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.

Last edited by Paul; 08-27-2017 at 12:39 PM.
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Old 08-28-2017, 01:14 AM   #9
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Heater fan relay # 18 is activated by power from fuse C7, which is powered through the ignition switch.

Check fuse C7.
Turn ignition on.
Check for voltage at C7.
Check for voltage at pin 86 of relay 18.

If no voltage at pin 86, replace C7.
If no voltage at C7, replace ignition switch.
If good voltage at both, replace the relay.

That's all there is between the battery and the fan switch.
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Old 08-28-2017, 06:51 AM   #10
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That explains why the fan switch works when 30 and 87 are jumpered. The fan switch is between the relay and the resistors/fan, not between the ignition switch and relay.
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2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.

Last edited by Paul; 08-28-2017 at 06:54 AM.
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Old 09-27-2017, 03:20 PM   #11
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Quote:
Originally Posted by particlewave View Post
Heater fan relay # 18 is activated by power from fuse C7, which is powered through the ignition switch.

Check fuse C7.
Turn ignition on.
Check for voltage at C7.
Check for voltage at pin 86 of relay 18.

If no voltage at pin 86, replace C7.
If no voltage at C7, replace ignition switch.
If good voltage at both, replace the relay.

That's all there is between the battery and the fan switch.
Thank you .
I will let you know how I get on.
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Old 09-30-2017, 10:13 AM   #12
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SORTED !
Paul and particle wave thanks for the helpful suggestions.

Spot on . I checked fuse C7 which until it was suggested I had no idea that it might be a fuse relevant to my problem and had only checked the obvious ones.

C7 had blown and on replacement everything works fine.

A big thanks to everyone .
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Old 09-30-2017, 10:16 AM   #13
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Spot on !

Thanks . I checked C7 and it had blown.

Thanks

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