There is an interesting diagnostic mode on climate control equipped cars that cycles through the raw sensor values providing data to the system. Using this you can see engine coolant temperature, internal/external/vent temperatures, internal humidity, solar radiation values and even vehicle speed.
From
http://www.hondafitjazz.com/manual3/en/html_en/000000000002163.htmlTo run the sensor input display mode, follow these steps
Turn the ignition switch to LOCK (0).
Press and hold both the AUTO and RECIRCULATION buttons, then start the engine.
After the engine starts, release both buttons. The display panel control unit will flash the sensor number and then the value for that sensor.
To advance to the next sensor, press the REAR WINDOW DEFOGGER button.
Sensor / Item / Displayed Value
1 Mode Positioning BIT
2 In-car Temperature °C
3 Outside Air Temperature °C
4 Solar Radiation Sensor Value: Dark=00, Flashlight=04, Cloudy=10, Sunny=65 10 kcal/m 2 ·h
5 Evaporator Outlet Air Temperature °C
6 Air Mix Opening (Low value indicates cooler air distribution, higher value indicates warmer air distribution) % of opening
7 Vehicle speed (Vehicle must be driven to display speed) 10 km/h
8 Engine Coolant Temperature °C
9 Vent Temperature Air Out (TAO) °C
A Humidity Sensor Value %
B Illumination duty Step
C Software version ——
To cancel the sensor input display mode, press the AUTO button or turn the ignition switch to LOCK (0).