A015

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The Sunload sensor is a light sensitive photodiode that controls the signal voltage to the Air Conditioning Programmer (ACP). This photodiode is different from standard thermistor type sensors and DVM resistance measurements will not produce accurate readings. The ACP monitors the voltage on CKT 590. When the sensor is in direct light the ACP senses low signal voltage. As the sensor becomes shaded, the signal voltage increases. Signal voltage varies between 5V (open circuit) and 0V (short circuit).

TEST CONDITION(S)

1. Ignition "ON."

FAILURE CONDITION(S)

Signal voltage less than 2% (short circuit) or greater than 98% (open circuit).

ACTION TAKEN

1. ACP uses a value of 98%, this allows for continued operation of the HVAC system.

2. ACP data parameter AD32 displays the actual Sunload sensor reading.


NOTES ON FAULT TREE

1. Display AD32, normal range is 2% to 98%.

2. High value indicates an open circuit. Jumper determines whether the wiring or sensor is the cause of the open.

3. Low value indicates a short circuit. Removing the sensor determines whether the wiring or sensor is the cause of the short.

4. Open is in the wiring. Jumper determines if the open is in the ground wiring or the sensing wire.

5. Determines if the open is in the sense circuit or at the ACP connection/ACP internal.

6. Note, if A015 is set without A013, look for an open CKT 407 between splice S241 and the sensor. (An open anywhere else in the circuit should also set A013.)

NOTES ON INTERMITTENT CONNECTION
If an intermittent DTC is being set, select ACP Snapshot Data for DTC and note value of ACP data parameter. Manipulate the related wiring while observing ACP data parameter. If a failure is induced, the displayed data parameter value will be outside the sensors normal operating range.