Questions about wiring harness for 1974 Options

[914Sixer]

Took me a minute because the harness is missing plug but it a a heated back window harness.

[GeorgeKopf]

Thank you Ian!

I'm having a bit of trouble reading the wiring diagram.

The wiring diagram has:
the door switches as brown/white (both wires to both switches?)
If both wires go to both switches, in parallel, won't both doors have to be open to break the circuit?
the parking brake as brown/yellow
the interior light as black/red

Do the door switches ground through the chassis?
Does the parking brake switch ground through the chassis?

Thanks.

George

[GeorgeKopf]

Thank you Mark.

I'm fairly sure that my rear window doesn't have any wires hanging off of it. (It is wrapped up and in storage right now.)

I also don't have a switch to turn it on. I'm guessing that I don't need to install that harness.

Thanks.

George

[iankarr]

@GeorgeKopf the wiring on my 73 harness doesn't follow that color scheme. Or the colors have faded. With regard to the door switches, I'm not sure exactly how the circuit works, but I know there are 4 connections on each switch. Looks like your diagram only has two, so it may not be for a 73. Recommend picking up a diagram from prosperos garage - http://www.colorwiringdiagrams.com. They seem easier to read. At least for me!

[ejm]

If both wires go to both switches, in parallel, won't both doors have to be open to break the circuit?

When a door is open the switch closes completing the circuit to ground

Do the door switches ground through the chassis?

From '74 on they ground thru the switch body

I'm not sure exactly how the circuit works, but I know there are 4 connections on each switch. Looks like your diagram only has two, so it may not be for a 73.

Correct, thru the '73 model year the switch had 4 contacts and grounded thru a wire.

Does the parking brake switch ground through the chassis?

Yes on all years

@GeorgeKopf @iankarr

[GeorgeKopf]

Thank you Ed.

It occurs to me that using just the two pole switches should work just fine. Grounding through the chassis or the brown wires should be identical.

Thanks.

George

[GeorgeKopf]

I've traversed the entire harness and am now deep into the dash components. It looks like at some time the wire from the light switch to the parking light indicator completely melted. The sheathing is stuck to multiple wires and there are brown marks everywhere.

Any idea what could have caused that melt down? I'm wondering if the wire rubbed through the light holder and grounded to the gauge. If so, I'm thinking of replacing all of the little bulb holders with ones that have an attached male flat connector. (Instead of the kind where the wire goes through the end of the bulb holder.)


Editors note: I was reading the 1973 fuse box wiring diagram and found this gem.
"High Beam indicator (Tach) and parking light indicator (Speedo) are unfused…"

So that explains that. (IMG:style_emoticons/default/idea.gif)



Thanks.

George

[914werke]

What is this harness for? It was in the box of electrical parts. I have no idea what year it is from.
George

That is the accessory harness to control the optional defrost R. glass. Its missing the relay board connector (hard to find) (IMG:style_emoticons/default/smile.gif)
It normally threads through the snorkle at the firewall, yours has been removed.

[GeorgeKopf]

Thanks Rich.

Now I'm working through the gauges and I think I've got it figured out.

My combo gauge looks like this:


Gauge wiring for 1973 Porsche 914.



Here are some pictures of the tangled mess of wires. I left off the gauge illumination (blue/black) because it was cluttering the pictures.
Combo Gauge
Tachometer
Speedometer

Please let me know if I've got this wrong!!! If so, I'll update the drawing for posterities sake.