A/C - Control Module A/C Indicator Blinking
Bulletin No.: 07-01-38-006Date: August 20, 2007
INFORMATION
Subject:
Information For Vehicles with HVAC Control Module A/C Indicator Blinking Due to Low Battery State of Charge
Models:
2007-2008 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2007-2008 GMC Sierra, Yukon, Yukon XL
with Manual Temperature Control HVAC System (RPO CJ3)
An Air Condition (A/C) button on the Heating, Ventilation and Air Conditioning (HVAC) control module may blink when the A/C system is activated. The blinking indicator will turn to a solid light after cycling the A/C button or ignition key.
This condition may be caused by a low battery state of charge on a PREVIOUS ignition key cycle. This condition may be due to situations were an unsold vehicle is parked for long periods of time as part of a dealership's unsold inventory. The A/C indicator begins to flash if the battery voltage falls below 9.5 volts. The low voltage condition may occur during an engine crank or if the vehicle is parked and a normal battery state of charge is not maintained.
If the A/C indicator continues to blink, use the Tech 2(R) to help determine the cause.
Connect the Tech 2 and build the vehicle.
Select Powertrain.
Select Engine Control Module (ECM).
Select Data Display.
Select Cooling/HVAC data.
Make sure that there has been an A/C request signal.
History should indicate any causes.
If necessary, refer to SI for further information on HVAC system diagnostic procedures.
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