B1610

B1610-AMBIENT LIGHT SENSOR INPUT CIRCUIT LOW (ATC)

B1610-Ambient Light Sensor Input Circuit Low (ATC):

WHEN MONITORED
Following the Start Up Wait Time after ignition on.

SET CONDITION
If the Ambient Light Sensor input is out of range toward the low voltage threshold.

POSSIBLE CAUSES
- (L24) auto headlamps signal circuit shorted to ground
- (L24) auto headlamps signal circuit shorted to (G939) sun sensor return circuit
- Sun sensor
- A/C heater control

NOTE: This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC is stored. Refer to HVAC System Test (ATC) for stored DTC test procedures. HVAC System Test (ATC)

DIAGNOSTIC TEST

1. CHECK FOR DTC B1610-AMBIENT LIGHT SENSOR INPUT CIRCUIT LOW WITH SUN SENSOR HARNESS CONNECTOR DISCONNECTED




Turn the ignition off.
Disconnect the Sun Sensor harness connector.
Turn the ignition on.
With the scan tool, erase HVAC DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read HVAC DTCs.

Q: Does the scan tool display: B1610-AMBIENT LIGHT SENSOR INPUT CIRCUIT LOW?

YES: Go To 2
NO: Replace the Sun Sensor. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

2. CHECK (L24) AUTO HEADLAMPS SIGNAL CIRCUIT FOR A SHORT TO GROUND




Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Measure the resistance of the (L24) Auto Headlamps Signal circuit between ground and the A/C Heater Control C1 harness connector.

Q: Is the resistance below 10k ohms?

YES: Repair the (L24) Auto Headlamps Signal circuit for a short to ground. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 3

3. CHECK (L24) AUTO HEADLAMPS SIGNAL CIRCUIT FOR A SHORT TO (G939) SUN SENSOR RETURN CIRCUIT




Measure the resistance between the (L24) Auto Headlamps Signal circuit and the (G939) Sun Sensor Return circuit in the A/C Heater Control C1 harness connector.

Q: Is the resistance below 10k ohms?

YES: Repair the (L24) Auto Headlamps Signal circuit for a short to the (G939) Sun Sensor Return circuit. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace the A/C Heater Control. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test