04 Tahoe A/C

[bogey]

Have dual a/c, drivers side goes to heat mode by itself. I have to turn vehicle off so a/c will reset. Is there a fix without replacing a/c control head. This might happen once a month or three times in one day.

[shadams]

Easy one. Either a dr side temp actuator or a software issue. I would start by updating the hvac software, which can only be done at the dealer. There is a bulletin for the 04 model year:

#06-01-38-003: Intermittent Ticking Noise from I/P, Poor A/C Performance, HVAC DTCs B0229, B0414, B0424, B3770, (Reprogram HVAC Control Module) - (Apr 27, 2006)


Subject: Intermittent Ticking Noise from I/P, Poor A/C Performance, HVAC DTCs B0229, B0414, B0424, B3770 (Reprogram HVAC Control Module)


Models: 2004-2006 Cadillac Escalade Models

2004-2006 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2004-2006 GMC Sierra Models, Yukon Models

with Air Conditioning (RPOs CJ2, CJ3)




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Condition
Some customers may comment on one or more of the following concerns:

• Intermittent ticking/clicking noise from the instrument panel.

• Recirculation mode does not work or Air Conditioning (A/C) system performance is poor during high ambient temperatures.

• Unable to control the driver side temperature.

• Unable to control the passenger side temperature.

• Unable to change the front system modes.

Cause
This condition may be caused by the Heating, Ventilation and Air Conditioning (HVAC) actuators that may hunt for the correct commanded position. This cycling may cause a clicking or ticking noise.

An overtravel of the HVAC system control doors may cause one or more of the concerns listed above. If an overtravel occurs, a Diagnostic Trouble Code (DTC) will be set, and the door will go to a preset default position. When a system door defaults, that door will stay at the default position until the DTC is cleared. After the DTC is cleared, the door will operate properly until the overtravel condition re-occurs.

Technicians are to perform the normal diagnostic procedures in SI for these concerns. If diagnostics show that the HVAC system door(s) travel below 5 counts (out of the lower range) or above 250 counts (out of the upper range), then update the software calibrations in the HVAC control module. The new calibrations were made available to dealerships as part of TIS2000 incremental satellite update version 2.5, which was broadcast to dealers in February 2006.

The new calibrations have been updated to compensate for the actuator overtravel condition, the actuator hunting and the ticking/clicking noises. The new calibrations effectively eliminate the codes listed above, the default position of the doors associated with the DTCs and opens up the feedback position value. The new calibrations should not be used unless the vehicle has one or more of the customer concerns listed above or a DTC listed above has been set. The new calibrations will not correct any other DTC or A/C system performance concern.

If that doesnt do it then it will need a dr side temp actuator. Good luck!