Hot Thing in my footwell?

[John Sims]

OK chaps, I've got a hot thing in my foot well. I want to know what it is and if indeed it should be hot. When I say hot I mean too hot to touch hot.

The thing in question is on the side of the footwell along side the accellerator pedal top link. It has a bracket below and a substancial bracket above and contains what seems to be two ceramic cylinders about 1" high and 1.5" in diameter.

As noted above, it gets very, very hot. I previously had my vac pipe for the boost guage behind it, until the pipe melted.

 

[924nutter]

John, that looks like a ceramic heater blower resistor, and on a slow speed setting that would get a bit hot due to the load on the resistance. I'm only guessing, but the shape and that green paint look familiar. On the later 924 it is situated behind the glove locker, but it looks like yours is above the adjustable foot rest

 

[Mark_Bennett]

Nice idea, but it's really Kryptonite, and John being Superman has activated it...

 

[John Sims]

Hi Nutter,

I'm not sure about the heater resistors as I was of the impression they are in a pack on top of the heater on the oval dash 944s.

That said, being dry, and daylight, about the only electrical ancillery running was the heater.

Another thought is - is it anything to do with the ABS?

 

[John Sims]

and John being Superman has activated it.

Nice thought Mark. At this point in time I feel more like "The Riddler" or "Captain Chaos"

 

[Fen]

ORIGINAL: John Sims

Hi Nutter,

I'm not sure about the heater resistors as I was of the impression they are in a pack on top of the heater on the oval dash 944s.

That said, being dry, and daylight, about the only electrical ancillery running was the heater.

Another thought is - is it anything to do with the ABS?

The ABS ECU lives behind the kick panel near the accelerator pedal, but IIRC it's a closed silver(?) box and I wouldn't expect it to get hot. When I stripped the door wiring from my Turbo I don't recall anything else in there apart from the ABS ECU.

 

[944Turbo]

The ABS ecu is to the right of the footwell behind the carpet (near the boot release switch). There is a resitor pack on the fan - don't know if its the only one. The radio signal amplifier is in that area but I don't think thats it - could be the other box at the edge of the picture. I don't know but will have a look next time i'm in the car.
On a similar vein in the passenger footwell when I had the ECU out above it there is a round Lid on a screw thread with a plastic bit attached to stop it getting lost, almost like the lid on a petrol can. this lid is at the bottom of a container of some sort - anyone know what that does?
Tony

 

[944Turbo]

thats the ABS ecu definately located then, yes silver box, multi way plug like the other ecu's.
Tony

 

[John Sims]

- could be the other box at the edge of the picture.

I think the other box is the one that you unplug, after reconfiguring one of the relays, to stop your headlamp pods going up on position 1. I seem to recall it being described a silver box about the size of a cigarette packet.

I'm erring on the heater control for my hot thing (it certainly warms up the footwell []) I can see that I'm going to have to carry out a trial run with and without the heater fan on to see if that cancelles that theory out.

 

[John Sims]

Found it! []

Nutter was almost right - they are resistors for the rad fans; hence two on the Turbo.

The resistors themselves are 52,5 W/O, 9 OHM series resistors part No 944 616 521 00.

Just because it is a Porsche and nothing can be simple, there are three different heat sink/mountings subject to year and right or left hand drive. Thought you'd be interested.

So now you know something else that you didn't. []

 

[944Turbo]

I will sleep more soundly now [][][]

 

[Guest]

The resistors themselves are 52,5 W/O, 9 OHM

A quick calculation indicates that the most that they can dissipate is 16 Watts each, so, at 52.5, they are suitably overrated. Presumably, the metal behind them should act as a heatsink ?

 

[John Sims]

the metal behind them should act as a heatsink ?

It certainly does. In the manner of a small convector heater . []

Based on your calculations John, that is the equivalent of having a 40W light bulb bolted to the underside of the bulkhead. No wonder it gets hot.

For those of us that like such things, if one was to put an indicator lap across the terminals of the resistor would this demonstrate when the fan comes on? More importantly, will it have any detrimental effect in demonstrating that the fan is on? - electricaly not emotionally that is. []

 

[eastendr]

ORIGINAL: John Sims

Found it! []

Top man !

Are you going to get it GUGU'd now [][][]