To Determine if The Switch is Functioning

WARNING: This page is about a different car, the 2005 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

Remove the glove compartment.
Start the engine.
Turn the A/C switch on.
Turn the fan switch on.
Connect the positive (+) and negative (-) probes of the voltmeter to terminal A and terminal B of the thermoswitch respectively. (The wiring harness connector must be connected to the thermoswitch connector.)
Inspect the voltage as shown below.
- If not as specified, inspect on/off points of the thermoswitch.
  
  Fig 1: Inspecting Thermoswitch Terminal Voltage
  Courtesy of MAZDA MOTORS CORP.
  
  Fig 2: Inspecting Thermoswitch Terminal Connector Continuity
  Courtesy of MAZDA MOTORS CORP.