Servo Assembly - Amplifier Test

Amplifier receives electrical signals from sensors and temperature control, then positions servo assembly with an electrical signal to give the required amount of cooling and/or heating. This signal from amplifier to servo assembly is fed through tester and read directly on voltmeter (with switch on Servo Amp). Driving voltage should be approximately 3-5 volts in either Heat or A/C mode and stabilized voltage should drop slightly. When driving to "Park", driving voltage is slightly higher and stabilized voltage will drop to zero.

If no driving voltage is observed when changing from one position to another, then check for the following:

• Ground wire disconnected.
• Amplifier disconnected.
• Blown fuse.
• Defective amplifier.

The servo should change position when driving voltage is at least 1.5 volts. If it does not change to all positions, then servo is defective or disconnected.