Download Self-Diagnostic Steps Step 1 – Monitor Diagnosis PURPOSE This step checks all the temperature sensing circuits. OPERATION Each time the HI switch is pressed, the code number in the SET section advances one number and corresponding data with the code number appears in the AMB section. Each time the LO switch is pressed, the code number reduces by one number and corresponding data with the code number appears in the AMB section. If the temperature shown on the display varies greatly from the actual temperature, check the sensor circuit first and then inspect the sensor itself. Step 2 – Actuator Tests PURPOSE This step checks all the actuators and the blower motor voltage. OPERATION When the HI switch is pressed one time, the first code advances. This code returns to “3” after it reaches “6”. Similarly, when the LO switch is pressed one time, the second code advances one number. After the code number “6” appears, it returns to “3”. EXPECTED TEST RESULTS During Step 2 testing, the auto amplifier will force an output to the affected actuators in response to the code number shown on the display. Checks can be made against the chart for actuator response and blower motor voltage.