Aux channel used for Cooling Fan

[mwman]

The Smiths gauges used in the UK as far as I knew were 10V not 12V.
To regulate a supply you need to have some "headroom" to cope with fluctations.
I made up a surface mount replacement that I installed in the old metal case.
On my old VW engined Skoda van, the temp sensor had two sensors in one case.
One fed the temp gauge the other the ECU for glow plug timing, I know this as the sensor played up!!

[NITROPIXIE]

Thats two really interesting posts. I think i may go ahead with the use of a semiconductor as a 10v regulator, seems a good idea to me.

At this stage i can think of 3 options for temperature monitoring, either:

Use a two pin thermistor as mwman used on his vw, although the cylinder head would need working to fit sensor

or

plumb in an additional sensor

or

have another discreet current sensing device in series with the smiths gauge, which can produce an output voltage proportional to current and dropping no voltage across it, hmmm??? not sure if there is anything like this that exists, how does a digital multimeter get a read out??

[NITROPIXIE]

had a play with the vintage smiths voltage regulator and couldn't get a steady output using a digital multimeter, didn't try testing with an analogue one, so i went with what others above have said and put a more up to date semiconductor one on.

I'm very lucky to have a fantastic workshop on base (Royal Navy), so for £15 per annum i have a massive dry warm workshop to work in all year round, just to brag . Well my friend had a spare set of clocks out of a vw polo with such a device i could rob.

20 mins later after working out the pin out and a lil soldering hey presto a steady 10v output. I didn't put it back into the original can as it'll be on the back of the clocks and so not seen.

Later injection minis had twin connector thermistors but not found out if this means it has two thermistors in one?