Nick. The circuit board behind the dash is notoriously unreliable. I had it burnt out 3 times and when it goes it burns the fuse which leave you without a speedo too. It was part of the impetus for me to change the dash because Borghi re-wires everything to eliminate the circuit board.

The problem with the circuit board is apparently that a lot of items, including the two speed heater fan, are earthed through the board and it is not robust enough to take it. The issue may have been complicated by the fact that I have aircon fitted.

I did finish up having problems with the new fuel gauge and temperature gauge both of which I have "temporarily adjusted" by adding parallel resistors in the circuit. In both cases there is too much resistance in the circuit to the sensors or between the sensors and the negative of the battery. My feeling is that this problem relates more to the new circuitry than the instruments themselves (which have been cross checked against the original) however I have not been able to get to the bottom of the problem.

To get back to your problem I am certain that there is a bad connection somewhere in your circuitry. Once the dash is off it is easy enough to check the power supply and the earth on both instruments. If they are both good the problem almost has to be in the line to the sensors. It can not be between the ECU and the engine or you would have problems with the engine running. The first thing I would do is to try unplugging and replugging, two or three times) the cable to the ECU, and perhaps also the MFU. It could simply be a poor connection between the connector and the pins on the ECU. Probably best done with the battery disconnected smile

Peter

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