I was working on the car, and noticed this plug hanging free beside the fuse/relay panel. I goes into the same wire harness as my O2 sensor.

 

It's the low octane plug. It will retard the timing if you can't get decent gas. It's supposed to be unplugged.

 

it is used for the tuning pot to set the CO adjustments on euro 928s

Marc
DEVEK

 

I stand corrected!

 

i find all kinds of plugs and stuff under my hood that i dont know what they do. yesterday while snooping around i found a switch that manually turns the fans on, which i though was cool, but not quite sure of the purpose of it.

 

Saxapeel,
Not sure if you were trying to be funny but I almost spewed beer when I read your post. Thanks!
Where is that switch? I'd like to know if it is on my 89 S4. Sorry to hear you are selling your Shark? Are you upgrading or moving on to other interests?
Good luck,
Tim

 

as jim puts it, im trading it in to buy an "appliance." something with good gas mileage that will take me to school/safeway and back. i found the switch on the passenger side: here is where it lays


this is what it looks like when i press it




i was sorta trying to be funny. but at the same time, im serious, there are like a million things not plugged in up there and i wonder if they are supposed to be.

 

Sax,

You are kind of right, kind of wrong in your naming of the switch. That switch isn't supposed to be laying off to the side. It should be mounted just aft of the cross bar attachment.

This is the engine hood switch. It is used for the burglar alarm. Also, the cooling fans will run after the engine is turned off when if the engine is hot. The purpose it to shut off the fans when the hood is open and the engine isn't running (Ignition in the off position or key removed). It is for safety.

 

Yep, that hood switch controls several things:

Fan cutoff when hood open for safety
Alarm trigger if hood opened
Under hood light on if headlight switch turned on.

Supposed to be mounted where the hood will contact when closed.

I have heard of this low octane wiring business... anyone know where it's supposed to be?

 

The low octane loop is for the 85-86 32v engine, since they don't have knock sensors that do that automatically like the 87+ 928s.

 

Hey, isn't the engine in the back? I thought I saw some wires or something back there.

 

Saxapeel,
Coffee spewing at work when I saw the photos of the "mystery fan switch."
I knew something must be awry.....never heard of such a "feature".
Thankfully, JayC67 posted a photo of its proper location and details of its function...
Best,
Tim