The LH sun load sensor is a light sensitive photodiode that controls signal voltage to the HVAC programmer. This photodiode is different from standard thermistor sensors and resistance measurements will not produce accurate results. The HVAC programmer monitors voltage on circuit 590 to the sensor. When the sensor is in direct sun light, the HVAC programmer reads a low signal voltage at terminal F10. When the sensor is shaded, the signal voltage increases. Signal voltage will vary from 5 V (open circuit) to 0 V (short circuit).
• | The ignition is ON. |
• | Circuit open or shorted. |
• | The HVAC programmer will default the system to dark or no sun load value. |
• | The default valve allows the system to operate. |
• | Using a Scan Tool . |
• | A history DTC will clear when 40 consecutive ignition cycles have occurred without a malfunction. |
• | HVAC programmer battery voltage is interrupted. |
Determines whether the sensor is operational.
Determines that the DTC was not set in error.
Determines if the malfunction is the sensor or an open or a short in a circuit.
Determines if the HVAC programmer or an open or short is causing the malfunction.
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
Note the value. Did the sensor counts increase from the noted value? | -- | Go to Step 2 | Go to Step 3 | |
Did the DTC reset? | -- | Go to Step 3 | Go to Intermittents and Poor Connections . | |
Refer to Measuring Voltage in Wiring Systems. Does the voltage equal the specified value? | 5 V | Go to Step 9 | Go to Step 4 | |
4 | Is the voltage greater than the specified value? | 5 V | Go to Step 5 | Go to Step 6 |
5 | Repair the short to the battery in CKT 590. Refer to Wiring Repairs in Wiring Systems. Is the repair compete? | -- | Go to Step 6 | -- |
6 | Measure the voltage between sun load sensor harness connector terminal A and DLC terminal 4. Refer to Measuring Voltage in Wiring Systems. Does the voltage equal the specified value? | 5 V | Go to Step 10 | Go to Step 7 |
Measure the voltage between HVAC programmer terminal F10 and DLC terminal 4. Refer to Measuring Voltage in Wiring Systems. Does the voltage equal the specified value? | 5 V | Go to Step 8 | Go to Step 11 | |
8 | Repair the open in CKT 590. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | System OK | -- |
9 | Replace the sensor. Refer to Sun Load Sensor Replacement . Is the repair complete? | -- | System OK | -- |
10 | Are all of the HVAC sensor DTCs present? | -- | Go to Step 11 | Go to Step 12 |
11 |
Is the repair complete? | -- | System OK | -- |
12 | Repair the open in CKT 1704. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | System OK | -- |
The sun load sensor is a light sensitive photodiode that controls signal voltage to the HVAC programmer. This photodiode is different from standard thermistor sensors and resistance measurements will not produce accurate results. The HVAC programmer monitors voltage on circuit 590 to the sensor. When the sensor is in direct sun light, the HVAC programmer reads a low signal voltage at terminal D10. When the sensor is shaded, the signal voltage increases. Signal voltage will vary from 5 V (open circuit) to 0 V (short circuit).
• | The ignition is ON. |
• | Circuit open or shorted. |
• | The HVAC programmer will default the system to dark or no sun load value. |
• | The default valve allows the system to operate. |
• | Using a Scan Tool . |
• | A history DTC will clear when 40 consecutive ignition cycles have occurred without a malfunction. |
• | HVAC programmer battery voltage is interrupted. |
Determines whether the sensor is operational.
Determines that the DTC was not set in error.
Determines if the malfunction is the sensor or an open or a short in a circuit.
Determines if the HVAC programmer or an open or short is causing the malfunction.
Step | Action | Value(s) | Yes | No |
---|---|---|---|---|
Note the value. Did the sensor counts increase from the noted value? | -- | Go to Step 2 | Go to Step 3 | |
Did the DTC reset? | -- | Go to Step 3 | Go to Intermittents and Poor Connections . | |
Refer to Measuring Voltage in Wiring Systems. Does the voltage equal the specified value? | 5 V | Go to Step 9 | Go to Step 4 | |
4 | Is the voltage greater than the specified value? | 5 V | Go to Step 5 | Go to Step 6 |
5 | Repair the short to the battery in CKT 590. Refer to Wiring Repairs in Wiring Systems. Is the repair compete? | -- | Go to Step 6 | -- |
6 | Measure the voltage between sun load sensor harness connector terminal A and DLC terminal 4. Refer to Measuring Voltage in Wiring Systems. Does the voltage equal the specified value? | 5 V | Go to Step 10 | Go to Step 7 |
Measure the voltage between HVAC programmer terminal D10 and DLC terminal 4. Refer to Measuring Voltage in Wiring Systems. Does the voltage equal the specified value? | 5 V | Go to Step 8 | Go to Step 11 | |
8 | Repair the open in CKT 590. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | System OK | -- |
9 | Replace the sensor. Refer to Sun Load Sensor Replacement . Is the repair complete? | -- | System OK | -- |
10 | Are all of the HVAC sensor DTCs present? | -- | Go to Step 11 | Go to Step 12 |
11 |
Refer to Intermittents and Poor Connections Diagnosis in Wiring Systems. Is the repair complete? | -- | System OK | -- |
12 | Repair the open in CKT 1704. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | System OK | -- |