23-NA-221

Service Bulletin Details

Public Details for: 23-NA-221

This service bulletin provides a procedure for sun load, ambient light, and charge indicator sensor replacement to correct a customer concern of a/c inoperative or a/c blows warm air.


- 2024 - 2023 -

Bulletin No.:
Service Bulletin
Date:
23-NA-221
January, 2024
TECHNICAL
Subject:
A/C Inoperative and/or Only Blows Warm Air Due to Faulty Solar Sensor
Model Year:
Brand:
Model:
Buick
Electra E5
2024
LYRIQ
2023
Cadillac
Chevrolet
Blazer EV
Equinox EV
from
VIN Breakpoint:
to
from
to
2024
—
—
Engine:
Transmission:
—
—
2024
Involved Region or Country
North America, Europe, China, GM Korea Company, Cadillac Korea (South Korea)
Condition
Some customers may comment that their A/C system is inoperative and/or only blows
warm to hot air.
Cause
The condition may be caused by an internal circuit fault within the upward-facing light
(solar) sensor. This circuit fault provides a high voltage signal consistent with an
extremely low cabin air/surface temperature reading and this causes HVAC system to
respond by delivering full heat.
Correction
Replacement of the solar sensor on vehicles with sensors that display voltages in scan
tool outside normal operating parameters (>4.5V).
Important: This technical service bulletin (TSB) can
only be completed by certified repair facilities who have
met all specific training, tool and equipment
requirements pertaining to the vehicle Brand and Model
serviced. Repairs must be performed by a technician
who has successfully completed the required training.
Important: Service agents must comply with all
International, Federal, State, Provincial, and/or
Local laws applicable to the activities it performs
under this bulletin, including but not limited to
handling, deploying, preparing, classifying,
packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict between
the procedures set forth in this bulletin and the
laws that apply to your dealership, you must follow
those applicable laws.
Copyright 2024 General Motors LLC. All Rights Reserved.
Service Procedure
Note: Conduct this procedure PRIOR to performing
standard A/C diagnostics methods, including checking
system pressures.
1. Place the vehicle in Service Mode.
2. Connect the scan tool and navigate to the
Passenger Compartment Air Temperature Sensor
voltage value, using the following path: Module
Diagnostics, [K9] Body Control Module, Data
Display, HVAC Sensor Data.
3. Verify Passenger Compartment Air Temperature
Sensor voltage reading is <4.5V, and the Left Front
Passenger Compartment Air Temperature reading
is within +/-10°C (50°F) of current shop
temperature.
3.1. If the voltage reading is >4.5V, it is necessary
to replace the sensor.
3.2. If the voltage reading is <4.5V, the sensor is
operating correctly. Continue with the
standard HVAC diagnostics in SI.
Note: Refer to table below for a reference of expected
voltages for a particular temperature.
Page 2
January, 2024
Bulletin No.: 23-NA-221
Solar Sensor Thermistor (REFERENCE)
Temperature
Solar Sensor Thermistor (REFERENCE)
Output (Volts)
95
203
0.21
°C
°F
Voltage
100
212
0.21
-40
-40
4.68
105
221
0.21
-35
-31
4.57
110
230
0.21
-30
-22
4.42
115
239
0.21
-25
-13
4.24
120
248
0.21
-20
-4
4.02
125
257
0.21
-15
5
3.77
-10
14
3.49
Parts Information
-5
23
3.19
0
32
2.88
5
41
2.56
10
50
2.25
15
59
1.96
* We believe this source and their products to be
reliable. There may be additional manufacturers of
such products/materials. General Motors does not
endorse, indicate any preference for, or assume any
responsibility for the products or material from this firm
or for any such items that may be available from other
sources.
20
68
1.70
25
77
1.45
30
86
1.24
35
95
1.05
40
104
0.89
45
113
0.76
50
122
0.64
55
131
0.54
60
140
0.46
65
149
70
158
75
167
0.28
80
176
0.24
85
185
0.21
90
194
0.21
Causal
Part
X
Description
SENSOR, SUN
LOAD & AMB
LGT & CHRG IND
Part
Number
Qty
84847757
1
Warranty Information
For vehicles repaired under warranty, use:
Description
Labor Time
0.39
Labor
Operation
0.33
4420370
Sun Load, Ambient Light,
and Charge Indicator Sensor
Replacement
Use
Published
Labor
Operation
Time
Version
2
Modified
Released December 15, 2023
Revised January 09, 2024 – Added a Note and Reference Table under Service
Procedure.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these
technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper
service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a
job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your
vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the
information.
WE SUPPORT VOLUNTARY
TECHNICIAN
CERTIFICATION


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