Electronic Mini Speedometer - Ignition Light Wiring Question

Greetings All

 

Purchased the "Smiths' Classic mini Speedo Electronic Speedometer - Purchased from Mini Spares  - Is made by Caerbont Automotive Instruments.

   I did send inquiry to Carerbont. ... no reply yet.

 

 Wondering if any one can guide me for the proper wiring of the RED Ignition Lamp.

 

I have all functions connected and working Except the ignition Light.

 

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Per their instructions :  {Brown / Yellow wire  -  Battery Warning Light - Connect to ground to Illuminate}

 

 

I for some reason can not imagine how this works / wires up

 

     The car has a bulb + Socket as original.

  The one Brown/ yellow wire goes to one side of the bulb.. the other side of the bulb is a White wire. that is always Hot when the ignition is on.

 

Has any one wired this speedo to the Red Ignition lamp?

 Can any one explain the wiring to this gauge better to me?

 

Any guidance or assitance appreciated

 

 Many Thanks

 

Justin Handy

NC, USA

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The white wire is ignition as you’ve said. The brown/yellow goes to the alternator where it is effectively earthed when the engine isn’t running. So with ignition on the lamp illuminates.
Then once the engine is running, and the alternator is producing voltage, the brown/yellow also becomes ‘hot’ so the lamp has 12v on both sides and hence goes out.

 

Don't be tempted to replace the lamp with an LED either, the alternator needs to ‘see’ the 12v ignition voltage initially in order to work. An LED (without some additional circuitry) doesn’t allow this to happen.

I can't help with any more info than above on wiring, but would like to know if the speedo was a recent purchase, as these have. Been listed as out of stock on MS for over a year now.

This one?

https://www.europasp...ace-90-mph.html

I bought mine from here https://www.digital-...peedometer-p327

,,,,, I did send inquiry to Carerbont. ... no reply yet.

 

Keep 'nagging' them but do it in a polite way, forward on your first email and just write something like " Hi, just needing a reply on this, thanks " with your original emails(s) in a string. They are slow, but will respond. Usually once you have their attention, they are good. If you don't get a reply in say 2 - 3 weeks, send me a PM.

 

 

Don't be tempted to replace the lamp with an LED either, the alternator needs to ‘see’ the 12v ignition voltage initially in order to work. An LED (without some additional circuitry) doesn’t allow this to happen.

 

That's quite correct of a stand along LED, however these Speedos do have a shunt in them to ensure correct Alternator excitation for those that need a shunt.
 

What triggers the electronic speedometer to calculate speed?

A speed sensor - either screwed into the gearbox or on the cable somewhere.  I think you can also use a hall effect sensor and suitable trigger

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What triggers the electronic speedometer to calculate speed?

 

I saw a link somewhere saying gps, which doesn't sound right and wouldn't be legal.

 

There's a piccy of the rear on Minimania that shows just a molex multipin connector. Seems likely it is a LED, but hopefully has the circuitry to wire in as a direct replacement. If you have a couple of left over wiring tails, preferably 1 white, the other brown/yellow, I'd be inclined to give it a go.

 

You could hook 'em up to 12v & reverse the polarity to see if the ign light shows both times.

.....

 

Re reading the original post it does have brown/yellow & presumably makes the "white" connection internally. I expect it'll work as the original light did under normal conditions. It might not show overcharge/low battery voltage though.

I don't have a Smiths gauge but mine uses magnets on the pot joint and a sensor

 Speedo Magnetic Pickup.jpg   84.42K   3 downloads

 

 

I saw a link somewhere saying gps, which doesn't sound right and wouldn't be legal.

 

There's a piccy of the rear on Minimania that shows just a molex multipin connector. Seems likely it is a LED, but hopefully has the circuitry to wire in as a direct replacement. If you have a couple of left over wiring tails, preferably 1 white, the other brown/yellow, I'd be inclined to give it a go.

 

All the warning lights and illumination in the Smiths electronic speedo are led, the unit is sealed.

Glad it was the plugs. I do like the speedo, it is nice to be somewhat accurate.

Sure had me freaked out for awhile. Sending a gauge to the UK for repair from the US has not worked out well in the past for me.

Terry

Now , upon first use .. and attempting to calibrate my speed signal to the gauge  .. I was having some Strange readings + Gauge jumping around and when calibrating the engine was running it was making up its own' signal.

 

 Remove sensor from trans = test with engine off = 1 rotation = gauge registers 1 rotation.

      Engine running = errant signals sent.

 

 Another TMF Member sent an idea... Resistor vs NON resistor Spark plugs.

 

          I changed the car to Resistor plugs ( to get rid of the extra 'electrical' NOISE) and  so far appears to have stopped the errant signal.

 

Video of sitiuation included.

 

https://photos.app.g...2hRgmhVu24w5c67

 

Doing final re assembly now = then off for a test drive + calibration test.
 

 

 

Thank you everyone for the guidance... NEW fancy speedo appears to be nice, bit of a headache.

 

 

The Speed sensors Mini Spares currently have for these are not suitable. The ones they used to have were OK.

As you find, these are only 1 pulse per rev. These Speedos need a minimum of 6 in order to register speeds below about 25 - 30 mph.

These will work properly;-

https://www.digital-...oso-models-p417

I have certainly had issues with both Daytona and Koso sensors. The other problem is that the "spindle" is not exactly the same as the Mini cable for either brand.

I am not sure who modifies them for use in a Mini, but some I got had a metal sleeve that needed adjustment to work and now they just come covered in shrink tube which seems to wear.