Gearbox wiring

[CO2MAX]

With at least a semblance of summer weather, and an influx of relatives and friends visiting, my build’s been on the back burner for a while. I’ve got to stage of wiring the gearbox (std Mazda 5 speed) and wondered which wires to connect. A quick search on here shows that the frontmost connectors (photo 1 circled) on the gearbox are the correct ones to use and attach to the green and green/black wires (photo 2). Both wires at the gearbox end appear to be blue and I seem to recall reading somewhere that it doesn’t matter which way round these are connected - I can’t for the life of me find that information again and hope that someone on here can help confirm this. I’ve got large hands which barely fit in the available space so don’t want to be joining these then finding I need to undo them.

Cheers, Craig 

[Jonathan Kay]

AMENDED: I've asked in another thread how Caterham are now wiring these.

Once you've found the right connectors:

The reverse light switch usually connects the earth side of the reversing light circuit. If there are two terminals then selecting reverse connects them together; if there's only one then it connects that terminal to earth through the body of the gearbox. It doesn't matter which way they're connected from the point of view of that circuit.

You can check which of the two wires in the loom is connected to earth by testing continuity with a multimeter.

Is that Green/Black or Green/Brown? I'm a bit concerned about these colours in an earth-switched circuit.

There's a particular issue with the earth connections on the Caterham LED integrated rear lamp unit. What have you got?

Do you have a wiring diagram for the car? Please let me know if you need a copy.

Jonathan

[AlastairA]

That's correct Craig - photo of my installation:

[CO2MAX]

Thanks guys.

Jonathan - on closer inspection one wire is green and the other green/brown (note to self  - get better garage lighting….or eyes😂) I’ve got the rear integrated LED light assembly. If you could send any wiring diagram you have I’d be much obliged - the kit is the most recent 420S with dry sump.

Alastair - your photo makes it very clear for me thanks. Can I also take the opportunity to say how useful I’ve found your blog throughout my build, and thank you for taking the time to prepare and share it with fellow owners/builders. For a complete novice like me it’s an invaluable resource.🙏

Cheers, Craig

[Jonathan Kay]

Private Message sent.

...

The discussion about the reversing light switch and the LED unit is here, and I've reactivated it to clear up the circuitry.

 

Jonathan