Final answer:
Both technicians are correct in their suggestions about the EATC system's issue. Technician A is right about the potential blockage of the sun load sensor's photodiode, and Technician B is correct in stating that the sun load sensor can be tested with an ohmmeter as it is a variable resistor. Option C. Both A and B is the correct answer.
Step-by-step explanation:
The question relates to the troubleshooting of an Electronic Automatic Temperature Control (EATC) air conditioning system. Specifically, it discusses a scenario where the system exhibits low fan speed operation during high-demand situations, such as in direct sunlight. The question poses two possible diagnoses:
- Technician A suggests that the low fan speed may be due to an obstruction covering the sun load sensor's photodiode.
- Technician B asserts that a sun load sensor is a variable resistor and can be tested with an ohmmeter.
Regarding Technician A's suggestion, it is true that if something were covering the sun load sensor's photodiode, it could lead to incorrect operation, potentially resulting in low fan speed when high cooling demand is needed. On the other hand, Technician B's statement regarding testing the sun load sensor with an ohmmeter is accurate as well, because a sun load sensor, which typically functions as a thermistor, is indeed a type of variable resistor whose resistance changes with temperature. Thus, it can be tested with an ohmmeter to check for proper functionality. Considering both statements, the correct option is C. Both A and B. Both technicians offer valid points that contribute to the understanding and troubleshooting of the EATC system's issue.