Coolant Temperature Sensor and Coolant Temperature Switch

Guest,

Not really sure that I understand the issue here. From my understanding of what you wrote I think the following may suffice:

You can purchase analog meters that have upper and lower selectable switch points built into the units. We use these types of instruments on some of our production equipment. The switches can be wired NO or NC to suit the application and they are typically set by setting a needle position on the analog guage. That way you can see the upper and lower switching points.

Hope this helps.

Regards

Mr. W.A Snow

They have already done that. I have two Ford Fiesta 1997 and 1998, which are small engined compact cars. Both have the same engine - known as Endura, 1000 cc, only 54 horsepower, but they do fine in the streets. They have a temperature sensor in a hose that comes from the engine block, that sends the temperature signal to the fuel injection central. The central reads the temperature value and adjusts the injection to match the engine conditions, combined with the air temperature, if the car is with air conditioning on or not, also making the auxiliary fan work in two different speeds, according the temperature and working conditions. Another temperature sensor located in the rear part of the engine block sends the signal to the panel indicator, as you stated. I'm sure that its for safety, in case of failure of the temp indication for the controller, you still have panel indication.

I would like to clear up some information here, if I may. Having been both a mechanic and degreed automotive engineer, there are typically three devices concerning temperature monitoring.

One, a temperature sending unit is used to send signals to the gauges to inform the driver of the engine temperature; a temperature sensor sends signals to the onboard computer for processing and response by the ECU, and a temperature switch switches electronic cooling fans on and off at a preset limit. Also note that some ECU's can switch fans on and off at various temperatures depending upon specific conditions.

Now, can you give us some background as to why you would like to integrate all the functions into one sensor? You're dealing with both variable voltages as well as simple "on/off" situations. If you're dealing with an ECU equipped vehicle, many of these are looking for these multiple signals during processing. Depending on what you're trying to accomplish, you could be opening up a can of worms by causing additional issues in trying to do what you would like to do.