924Board.org

[keithiopian]

for background, i have a 1978 924 that only has 30k miles on it, but sat in a garage for about 15 years, so there is the delightful excitement of never knowing whats going to go out next.

now, for a time there was a gremlin lurking beneath my hood, draining my battery slowly and causing overheating. This gremlin I have tracked down to a small little electrical box that i am guessing is a relay of some sort just above the radiator. it is completely fried, brown and cracked. it sits tucked under a little lip at the very nose of the car, just to the left of the right headlight if facing the windshield from the front.

now this is all well and good, but for the life of me i cannot find in my haynes any mention of the thing, and on websites under "cooling" and "electrical" etc I can't seem to find something that resembles it...it is held down by a bracket that reads "1.8" and says on it "481905051A BERU WZ18-2F" I have tried searching for all these with no success.

So, the part has to be replaced no matter what, making my first question "what is this part, and where can i get a replacement?" However, though it could have fried from old age, it could also be an electrical problem in the system that connects to it, which would naturally fry the new part if i were to replace it. So all you vets out there, can you help out a newbie with this? Thanks!

Keith

[!tom]

Is that your current limiting resistor for the fans?

A resistor shouldn't leak current; it should limit the amount of current that other things connected with it use.

I would suspect a short somewhere else in the wiring, likely having to do with your radiator fan or radiator thermal switch, and this resistor is preventing an all-out short.
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78 924 NA
5-lug

[keithiopian]

a definite possibility...as an additional piece of information though, my car battery would die at random times when the resistor was blown and the leads were still connected. (or whatever it is, although my limited electrical knowledge after taking it apart and finding a springlike-structure hints pretty strongly it is indeed a resistor). However, after disconnecting one of the leads, there's now no more battery problem. If there were a short somewhere else in the line, wouldn't it still be draining? maybe its just me being wet behind the ears...

[D Hook]

Keith: Can you get a pic of this thing? I can post it for you, if needed.
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'80 924 n/a SOLD

[Mike924]

Strange... The part number looks as though it could be a valid VW (Porsche?) number. In which case, the 905 would indicate an ignition part of some sort (backed up by the fact that Beru are suppliers of such parts).

If it is the radiator fan current-limiting resistor, it's an unofficial mod (probably using a random VW part). The proper place for this resistor is up behind the fuse box inside the car.
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1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org

[Nobbi]

Hello,

my car has the same thing at the the same place.So it will be a regular serial part.Maybe only for certain model and year.My car is euro-spec XK build in april 1977.
Never had a problem with it, so , dont know what for it is.

Nobbi

[924RACR]

The early cars had a box-like fan resistor mounted above the radiator. Perfect place for corrosion to kill it. Later cars, it was moved to the firewall behind the dash - behind the tach, actually.

This is the resistor that supplies power to the fan when ignition is off, and allows the temp switch to turn on the fan at low speed.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[Mike924]

Mystery solved.

Thanks, Vaughan.
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1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org

[keithiopian]

yes, thanks vaughan! any idea where i could get a replacement?

[924RACR]

Well, for starters I'd remove the connections so it can't kill your battery. Then I'd reroute the wires to a safer location and retrofit the later part. I'd say it's not even necessary to put it in the dash, just get it away from the bottom edge of the hood where all the water will drip on it!
_________________
Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[augidog]

I think he is describing the relay that runs the fan when the ac is turned on.
Same location as the resistor.
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1978 924 95 mile daily driver.
Audi TB/POR174M/High Flow Cat/2.25" exhaust
I knew that positive thinking thing wouldn't work.