Apparatus and method for calibrated testing of a vehicle electrical system

A method of testing the air conditioning system on an automobile including the steps of activating the air conditioning system;

• positioning a temperature responsive resistive element in front of the air flow from the air conditioner;
• detecting a change in voltage drop across the resistive element;
• comparing the change in voltage drop to a predetermined voltage magnitude;
• and
• determining if the air conditioning system is providing cooling air by observing if the change in voltage drop is substantially the same as the predetermined voltage magnitude, which would indicate acceptable or proper operation, or if the change in voltage drop is substantially different from the predetermined voltage magnitude, which would indicate a malfunction or improper operation.

A method of testing portions of a vehicle including:

• coupling a transducer to a vehicle component whose characteristic is to be measured;
• producing a voltage by the transducer as a function of the vehicle component characteristic;
• comparing the transducer voltage to a predetermined voltage magnitude;
• determining if the vehicle component characteristic is within limits;
• storing the option content of a vehicle to be tested in the comparison means;
• indicating to an operator of the test whether or not to conduct an examination of the vehicle;
• and
• changing the magnitude of the predetermined voltage magnitude used for comparison as a function of previously measured voltage levels associated with particular component characteristics of the vehicle.