GMC Chevy Colorado 2023 Manual page 113

Compressor Solenoid Valve. When the A/C switch is
pressed, the BCM grounds the variable displacement
solenoid using a (PWM) signal in order to determine the
amount of compressor displacement. The performance
of the A/C compressor is regulated based on
cooling load.
B160 Inside Air Moisture and Windshield
Temperature Sensor
The windshield temperature and inside moisture sensor
includes the relative humidity sensor, windshield
temperature sensor and humidity sensing element
temperature sensor.
This sensor assembly provides information about:
Relative humidity level at windshield (passenger
compartment side)
Temperature of the windshield (passenger
compartment side)
Temperature of the humidity sensor element
The relative humidity sensor measures the relative
humidity of the passenger compartment side of the
windshield. It also detects the temperature of the
windshield surface on the passenger compartment
side. Both values are used as control inputs for the
BCM application to calculate the fog risk on windshield
compartment side and ability to reduce fuel
consumption by decreasing A/C compressor power to a
minimum without causing any fog. The sensor will also
enable partial recirculation mode in order to improve
heat-up performance of the passenger compartment
under cold ambient temperature conditions without the
risk of mist build-up on the windshield. The humidity
sensor element temperature sensor supplies the
temperature of the humidity sensor element. It is only
needed if the thermal contact between the humidity
sensing element and the inside windshield surface is
not sufficient.
The sensor is a LIN device, and the sensor values are
transmitted to the BCM via serial data.
When equipped with CE1, the sensor is part of the
B117A Windshield Outside Moisture/Ambient Light and
Humidity Sensor LIN windshield sensor array, and the
windshield temperature and humidity values are
transmitted to the BCM via serial data.
B10D Sun Load Temperature and Ambient Light and
Security Indicator Sensor
The ambient light/sunload sensor includes the solar
sensor and passenger compartment temperature
sensor.
The solar sensor is connected to a low reference and 5
V supply through the BCM. As the sunload increases,
the sensor signal voltage also increases and vice
versa. The signal provided to the BCM varies between
1.2 4.85 V.
The passenger compartment temperature sensor is a
negative temperature coefficient thermistor, connected
to a low reference and 5 V supply through the BCM. As
the air temperature increases, the sensor resistance
decreases. The signal varies between 0 5 V.
Bright or high intensity light can cause the vehicles
interior temperature to increase. The HVAC system
uses the sensor values and compensates for the
increased temperature to maintain the system settings.
2023 - Colorado Electrical Body Builder Manual
HVAC - Automatic
Air Delivery
The BCM controls the distribution of air by the use of
recirculation and mode door actuators. The modes that
may be selected are:
Defrost: windshield outlet
Panel: dashboard outlets
Floor: front footwell outlets
Defog: defrost + floor
Bi-level: panel + floor
Tri-level: panel + defrost + floor
Hi-level: panel + defrost
The desired air distribution mode can be selected with
the air distribution switches at the HVAC control. The
HVAC control delivers the values to the BCM via serial
data. The BCM sends a request to the mode door
actuator to move the door to the required position.
Depending on the position of the door, air is distributed
through various ducts leading to the outlets in the dash.
When defrost airflow is active, the BCM will move the
recirculation actuator to outside air, to aid in reducing
window fogging. When defrost is selected the blower
motor will be activated, regardless of the coolant
temperature. A/C is available in all modes.
Refer to the owners manual for operation of the HVAC
controls and mode selection.
Recirculation Operation
The recirculation switch is integrated into the HVAC
control. The selected recirculation setting is sent to the
BCM via serial data. The BCM controls the air intake
using the recirculation actuator. In recirculation mode
the recirculation door is positioned to block outside air
from entering and circulate the air within the vehicle. In
outside air mode the recirculation door is positioned to
route outside air into the vehicle.
Recirculation is only available if the defrost mode is not
active. When the defrost mode is active, the
recirculation actuator positions the recirculation door so
that outside air is circulated to the windshield to reduce
fogging.
In automatic mode the values of the sensors are used
as inputs for the BCM to calculate the fog risk on the
passenger compartment side of the windshield. The A/
C compressor and the defrost mode may be activated
to prevent or remove fog on the passenger
compartment side of the windshield.
In automatic mode, a partial recirculation mode may be
commanded to accelerate cabin heating or cooling and
reduce energy usage. The recirculation indicator
remains illuminated at all times, regardless of the actual
operating mode determined by the system.
Heating and A/C Operation
The purpose of the heating and A/C system is to
provide heated and cooled air to the interior of the
vehicle. The A/C system will also remove humidity from
the interior and reduce windshield fogging. Regardless
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