A simple wiring question ???

[Crazy Horse]

A question to the wisdom collective:

I pulled my 3.0 engine from my 1979 911SC Targa to replace the clutch and decided to detail the engine compartment.

Laying across the engine (loose and not hooked up) was a 4.5-foot long plastic sheath that looked like a vacuum line from an American car. I laid it aside.

I then opened up what I thought was a vacuum line and found one brown 14 to16 guage wire and one gray 14 to16 guage wire. The brown wire connected to the "bolted" ground behind the fuel filter on the Driver's side wall of the engine compartment. The gray wire leads to underneath the "brain" mounted on the Driver's side of the engine compartment.

Does anyone have any idea what these two wires are for???

THANKS !

[afterburn 549]

a pic would help

[2ndTARGA]

According to the factory SC wiring diagram, the only two places Gray wires seem to be used are:

1. Reverse switch between gearbox and rear end wiring harness (Back-up lamps)

2. Headlamp switch to License Plate lamps.

Not sure why either of these would have been hanging loose near your engine, but the License Plate lamps also use a brown ground lead. (The reverse switch from the gearbox does not)

Hope this helps. You might be able to confirm by checking for +12 on the gray wire under various conditions.

Ron

[2ndTARGA]

Bingo!

I found a supplementary section of the wiring diagram that covers the (drum roll please......) Engine Compartment Light. I didn't know there was one.

This device is shown as having one Gray and one Brown wire. The Gray wire goes to T6 "Cable connector, sixfold, in engine compartment, rear left" which is at the relay panel as you described.

Ron

[Crazy Horse]

2ndTarga,

It absolutely is the engine lid light. Thanks all for the help !!!

[jcunning]

Can someone post a picture of the engine lid light?

Is it the same or similar to the light on the trunk lid?

I'm asking because my car doesn't have one and I can't seem to find any reference to it on Pelican or the PET CD.

Part #'s would be great as well.

[billybek]

Not the same as the trunk light.
It has a sliding shield that I think (mine doesn't work) turns on the light.
If no one else posts a pic, I will try to when I get home..

[2ndTARGA]

No Photo, but it is listed in the Pelican Parts Catalog: (Porsche 911 & Carrera Lights and Lenses - Page 8)

911-631-315-01-OEM Rear Engine Compartment Lamp Assembly, 911 (1974-89)
Brand: Genuine Porsche
$52.00

I've never seen one either, but hopefully they have an on-off switch (as opposed to the trunk lamp) If not, then it's no wonder the wires were disconnected in this case.

Ron

[billybek]

OK, two pictures of the uber wonderbar engine bay light that doesn't work!
The lamp is shielded from dirt and heat by a sliding guard. I believe that the guard completes the circuit to ground when fully open allowing the lamp to operate.

[billybek]

Side view!

[billybek]

Hey, I need to clean under there!

[Cooper911SC]

My engine compartment light was MIA when I bought my SC. I got one at the Pomona, CA swapmeet and installed it...it didn't work...but then I figured out that you have to have the key in the 'on' position and IIRC the headlights/parking lights on.

Billybek...try turning on your headlights/key and then open the little cover to turn on the light.

Hope this helps.

Cheers, Cooper

[billybek]

Thanks!
I am going to give that a try..
If memory serves me well, i think this same light was inside the glove-box in my 74 Thing!!

[billybek]

I thought that light looked familiar! The same light in the glove box of a 74 VW Thing.