[Gmecm] Ignition off fan

[Robin Handley]

> I can only assume that my Fan flicking ON and OFF a few times, as (real -
> i.e. not simulated) CTS approaches the Hot Fan ON threshold is due to
> sufficient noise to defeat the ON/OFF hysteresis, and that the 1Hz ALDL
log
> isn't showing all of the dips. It should take only one value below Hot Fan
> OFF to turn the fan off. I will see if I can temporarily improve the CTS
> ground to see if this goes away...

Well the results of that test seem pretty conclusive:-

- with CTS grounded to chassis (same point as Fan ground!!!), CTS value
flicked about and the Fan kept flicking ON and OFF;
- with CTS grounded to engine, CTS value was much more stable and Fan came
ON once only, and stayed on until the CTS value dropped.

So, I shall be grounding my CTS to pin C10, as it should be... (my excuse
for the bodge in the first place was that I originally just lashed up the
CTS to experiment with the ECM controlling my fan, and I didn't want to mess
about with my nice TPS ground (already connected to pin C10) for the sake of
an experiment!) :-)

Robin