924Board.org

garyj19 · Joined: 04 Sep 2005 Posts: 226 Location: Connecticut

anyone know what the fan resistor is? i dont.

i apparently need to know what resistance and wattage it is...

thanks.
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early 77 924 na

leadfoot · Posted: Thu Oct 05, 2006 1:54 pm Post subject:

behind the dash, to the left of the glovebox on a RHD car big round cremaic thing ....
so if your car is LHD try the same spot i.e next to the steering wheel or check the other side...
BTW you can just bypass it... IMO I don't think it's worth using it.
Leadfoot
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1981 ROW 924 Turbo -
carbon fiber GT mish mash
LS1 conversion in progress...

D Hook · Joined: 02 Nov 2002 Posts: 3158 Location: Omaha, NE

In this picture, it's the big, round white disc with three wires coming off it in about the middle of the sheet metal behind the dash. Hope that makes sense. In the picture, look just below the center of the A-pillar.

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'80 924 n/a SOLD

924RACR · Posted: Thu Oct 05, 2006 10:00 pm Post subject:

He's got a 77 - it would be up on top of the radiator, in my experience, and exposed to the elements. It's a big long rectangular dealy-o. But I'm sure the reason he's asking for the electrical details is because his is corroded. The location makes sure plenty of water gets dripped on it from the front edge of the hood. They realized their mistake eventually and moved it to the inside cabin location around 78-79. But he doesn't have that. No doubt he's looking to upgrade.

Gary, I'd recommend just getting a used modern one (as pictured) from a wrecker, like 944 Ecology, if the parts places don't have them new. I doubt you'd be able to get something from RadioShack that would tolerate that current.

I would guess it cuts down the voltage roughly in half when in use. Could guesstimate a resistance and wattage value from that with Ohm's Law...
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

D Hook · Joined: 02 Nov 2002 Posts: 3158 Location: Omaha, NE

Didn't see the '77. My bad.
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'80 924 n/a SOLD

Smoothie · Posted: Fri Oct 06, 2006 1:20 am Post subject:

This-> http://www.924.org/parts/parts.htm shows the later resistor (which you could use) is rated 5.2 ohms and 50W.
The OE part is relatively expensive though.. You could use two 2.7ohm 25W resistors wired in -series- instead, at $1.30 each -

[Scratch that yellowed-out nonsense]
You could use two 10ohm 25W resistors wired in =parallel= instead, at $0.95 each -
http://www.action-electronics.com/resist25.htm
-or one 5.0 ohm 50W at $6.25 -
http://www.action-electronics.com/resist50.htm

[-and thanks to RC for the correction below.

]
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

geddes66 · Joined: 10 May 2003 Posts: 129 Location: Bakersfield CA

That is some of the info I need right now! The resistor in my sons '77 car is nothing more than a coiled wire in a bed of crumbleing ceramic debris. But still working.

He is away at Navy boot camp and I am trying to get all the issues worked out before he gets home. ("All" being a relative term)

How many amps does the fan draw? 50W seems kind of low that would be like 4 amps (48 watts at 12 volts) or is the resistor value half of the full power draw?
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The Porsche is now my son's, my car is cooler, slower but cooler.

Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

The resistor drops the voltage at the fan down to about half, so the current (flowing in both items, fan and resistor) is correspondingly halved. This is known as Ohm's Law.
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1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

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RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia