Wiring diagram for MkII 1.6 Instruments Cluster

Technical Area Electrics & ICE
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  1. My model of MX-5 is: __2005 MkII 1.6
  2. I’m based near: __Egham
  3. I’m looking for technical help or recommendations on: __Instruments

Hi, does anyone point me to a wiring diagram for the instrument cluster? I actually want to know which pin on which connector drives the speedo and what signal is coming to it - i.e. is it a digital sequence of pulses or an analogue signal? I’m building a special using an MX5 as a donor and the tyre O/D will be about 15% greater than standard, so I need to calibrate the speedo accordingly.
Thanks, Adrian

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It’s an orange (terminal 2M) wire and a yellow (terminal 1M) wire and they’re in different plugs strangely enough. I’ll get back to you with a signal…

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The test for the sensor is to connect a voltmeter across it and spin it to see if it generates a voltage. I’m going to guess it’s an inductive sensor.

The speedometer operation description is something like the following…

The instrument cluster receives vehicle speed as an 8 pulse signal from the speedometer sensor at 8202 pulses/hour the speedometer will read 1 mph.

Any help?

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This is great, thank you. I’ll get a scope on the signal. Now to figure out how to increase the frequency of the pulse!

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I suppose it could be a 2 wire GMR sensor, I’d interested to know if there is 12 volts on the Orange or Yellow wires.

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I should be able to look at the trace on the scope to see what signal looks like, and it’s voltage swing. This will take me a few days - I’ve disconnected the battery as I’m in the process of stripping the car right down. When I’ve finished, hopefully the engine will still run. By jacking one rear wheel I should be able to check the indicated speed against the pulse frequency. I will get to this!

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Thanks, I be interested to see the trace/voltages.