After changing a car battery or getting your vehicle back from the shop, it's often necessary to reprogram the radio. The 2004 Chevy Trailblazer can come with any of three different factory radios, depending the package that came when the car was purchased. Fortunately, all three have similar programming methods, which take just a few clicks of a button.
Insert key into ignition switch and turn to the "acc" (or accessory) setting. There is no need to start the engine. Turning the key to accessory engages the Trailbalzer's electrical system without the waste of burning gasoline.
Press and hold the "H" button until the correct hour appears on the radio display. "AM" or "PM" will appear on the display. Note that on some models, the hour button is indicated by "HR".
Press and hold the "M" button until the correct minute appears on the radio display.
Note that on some models, the hour button is indicated by "MN".
With the key still set to "acc" or accessory, depress the power button located in the top-left corner of the radio.
Note that an unprogrammed radio may tune to an unused bandwidth and produce static. Turn volume dial counterclockwise to decrease volume if the interference becomes bothersome.
Factory-installed Trailblazer radios allow for up to 30 preset stations on any of AM, FM1, FM2, XM1 or XM2 bandwidths. Depress "BAND" button to select from among those.
Turn the "Tune" dial to reach the desired station. Alternatively, depress the right arrow on the "SEEK" button for the radio to automatically search for the next available station. Stop at the desired station.
Depress and hold any of the pushbuttons numbered 1 through 6. The radio will beep once when the station is set. Pushing this button in the future will return the radio to the preset station.
Repeat steps 2 through 4 for each station desired in the preset.
