Apologies all, I normally get an alert when someone replies to a thread I am posting on, nothing on this one?
Anyway, thanks to all for your contributions and to clarify, the switch detects higher temperatures than considered OK by Mr T. As per
@StarCruiser the AC is cut out to prevent it loading the condenser with heat, this would added to the engine cooling radiator, and given the extra work the AC compressor adds as per
@frank rabbets comments this too may help.
So story time, a couple of years back I converted the strip of plain plastic (mines manual) between the speedometer and rev counter to hold a row of LED's, these would convey extra information about what was going on under the bonnet. First attempt looked crap, it worked but for an OCD person such as I am, simply not good enough.
I drew up a design to be sent to a screen printer, in the meantime had asked
@karl webster send me the centre piece from an automatic transmission dashboard, this normally told the driver of the gear range selected.
So I had graphics added to a piece of 'dead fronted' material, so nothing is shown as per the OE dash when not illuminated.
This was integrated with my electric engine cooling fan, it showed different speeds, loss of coolant, loss of oil pressure (which the stock 80 only has a gauge) not noticed until it is too late, and of course other 'stuff'.
I am trying to get the overheat warning to work accurately enough to not trigger false alarms, by having the sensor cut out temperature, I can extrapolate the temperature switch needed to trigger the LED and activate the buzzer paralleled with low oil pressure and coolant loss indicators.
I had considered the AC switch but was not quite sure if when open circuit there would be a live potential when not earthed? If yes this would feed back to my LED's and they do not like that.
Also in the interest of future fault finding, I try to keep wiring mods as isolated from OE wiring where possible, so the switch is to be independent.
The post from
@SeaJay mentions AC still working @112 C°, I am thinking this a good ball park figure in fact, would be happy to switch off the AC manually at that temp however, our friends across the pond AC switch on their petrol version cuts at 107 C°.
EDIT: I have just seen
@Firewout's post, how I missed that in the FSM I don't know, thank you for that clarification mate, you are in a beer credit!
So I am now working on finding a sensor, many thanks again.
Regards
Dave