Relay for rear syncro diff

[vr6will]

Does anyone know to what pin and plug on the fusebox the black wire that comes from the relay behind the centre console for the rear diff?

[Chris S]

I asked Mark (slateford) to have a look on his Rallye and here is what he came up with for the 02C gearbox reverse light switch.

From top to bottom,

1. Brown
2. White
3. Red/black
4. Blue/black

The last 2 are definitely red and blue respectively but it looks like they have black as part of the colour scheme, or it’s just dirt.

Mark

Having checked the wiring diagram the colours are correct & here is what they do

1. Brown = To earth via switch (on in 1 2 3 4 & 5 gears) for the diff freewheel relay
2. White = Connection to the diff free wheel relay

3. Red/black = Power in from fuse 14 for the reversing lights
4. Blue/black = Switch on power out for the reversing lights

Note that there are 2 totally seperate circuits contained within the one switch.

So it appears that the normal or at rest position of the freewheel is off or locked out I.E. no freewheel, and you only engage or enable it when you select one of the forward gears.
It looks to me like a consequence of this could be that if you dont have the electics & vacuum connected up at your rear diff then your freewheel is locked out of the circuit, which means that there is no free overrun, and the rear wheels can not rotate faster than the fronts without the VC unit having to take up the slack, so having smaller rear tyres is as much of a no no as having larger ones.

[vr6will]

i have found a wiring diagram for this, when i work out how to upload it, i will…

[no such user]

Alternatively you are welcome to email it to me and I’ll host it for you, Will (I’ll be needing it fair soon anyway!).

[Slateford]

Any luck with the wiring diagram?

[scruffydubber]

I would be very interested to see the wiring diagram too.

I don’t really understand the diff freewheel, could somebody explain?
What would be the downside if pins 1 and 2 where perminatly connected?

Sorry if this is obvious, I’m still learning lots about the syncro system.

thanks for any info

[vr6will]

its on backup at the mo, my computer died and not restored everything yet, i will do it soon!

[Author]

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