Extra connection on rear of speedo?

[Smiffo]

Evening all.

This is a strange question, but thought I would throw it out there.
Changing the blue ribbon out on the back of my clocks today, and noticed the old one had a `plug` that goes into the back of the speedo...

Now I didn't think anything of it until I put the other in - you guessed it - no plug...

Oddly I can't think what it could be for.
Clearly the speedo works via the speedo cable, and there is nothing else on the display that could need a connection, so what is it for?

[silverbullet]

Pulse output for factory cruise control aka VSS (vehicle speed sensor) which is also useful for maximizing economy from Subaru conversions.

[Smiffo]

Pulse output for factory cruise control aka VSS (vehicle speed sensor) which is also useful for maximizing economy from Subaru conversions.

Cheers SB.

My van deffo never had cruise control.
Here are a few pics below:



The above pic shows the plug on the blue ribbon - this goes into a plug on the back of the speedo that has 6 pins.

I Googled the VSS, and that looks like it fits next to the speedo cable ( I think. )

I have loads of `gubbins` behind the speedo too.
Could it be the `buzzer of doom circuit or something similar?` That is the only thing I can think of that late vans had that maybe early didn't...

Failing that I will just fit it back in tomorrow and see what doeasn't work

[marlinowner]

Are we talking about the oil pressure warning circuit? It's built into the speedo with a six pin connector. Not present on early vans. I bought a pcb (still available from Vw classic parts) that seems to be a hybrid type with later 14way connector and rev counter but no oil pressure circuit connector.

E D I T: your post came up whilst typing!

[Smiffo]

Are we talking about the oil pressure warning circuit? It's built into the speedo with a six pin connector. Not present on early vans. I bought a pcb (still available from Vw classic parts) that seems to be a hybrid type with later 14way connector and rev counter but no oil pressure circuit connector.

E D I T: your post came up whilst typing!

Yeh, I think that might be it.
Now I'm into limbo land I put the new ribbon in to get my new rev clock working ( it came with it ) and now it seems I may lose my buzzer of doom

I need a think....
I don't really want to lose that, not if I can help it....

[marlinowner]

I hard wired mine with the aid of the Haynes circuit diagram and and old PC power supply - the main motherboard power connector had near enough the same pin spacing and cut down nicely.

Your photo is definitely the oil pressure warning connector.

[Smiffo]

I hard wired mine with the aid of the Haynes circuit diagram and and old PC power supply - the main motherboard power connector had near enough the same pin spacing and cut down nicely.

Your photo is definitely the oil pressure warning connector.

Hard wired the Buzzer of doom, or hard wired the whole `blue ribbon?`
Maybe I need to think about doing that. I don't want to lose the buzzer, and a rev counter sat there grinning at me without moving will wind me up

[silverbullet]

Sorry that was a red herring about the vss/cruise

[Smiffo]

Sorry that was a red herring about the vss/cruise

No probs - at least I now know what a VSS is..!!

[marlinowner]

Just the buzzer circuit. Here are the pins of the six way connector, labelled as per the wiring diagram in Haynes.

0.3
1.8
Space
15
A
-
1

[Smiffo]

Just the buzzer circuit. Here are the pins of the six way connector, labelled as per the wiring diagram in Haynes.

0.3
1.8
Space
15
A
-
1

Hi Marlin, what do those values relate to?
I don't imagine 0.3 ( for example ) is pin 0.3

I think I will draw out the old blue ribbon first. See what pins they go to, and then compare to the new one I have.
I may be able to see something then - my wiring diagram skills and interpretation is next to zero

[marlinowner]

If you have a Haynes manual, they are the labels used on the circuit diagram for J114 which is the buzzer circuit.
Section 12 page 28.
Then you can decide where to connect the wires. Most complicated bit is cutting the track from pin 13 of the 14-way connector, which goes to the oil pressure warning light, and connecting each side of the cut to the 0.3 and A pins of the buzzer connector.

[marlinowner]

[Smiffo]

Ok - found it.
Mine is section 12 page 29, but diagram is the same as yours.

I'm going to try get my head round this now. Why oh why do I start these things...??

[marlinowner]

Just go easy with the soldering iron on the pcb!