Hummer 2003 H2 Owner's Manual page 299

Receiver Extension (If Equipped)
Use the receiver extension with the front receiver and
-
various light duty accessories such as bike racks.
The receiver extension was not intended for heavy
use such as trailer towing, winching or vehicle recovery.
To use the front receiver with the receiver extension,
do the following:
A. Receiver Extension
B. Wing Nuts
1. Locate the receiver extension in the rear of the
vehicle where it is attached to the spare tire
mounting plate.
2. Loosen the wing nuts holding the extension to the
-
duty
spare tire plate and remove it.
3. The extension attaches to the front receiver exactly
as the power winch platform does. See "Power
Winch Platform" following in this section.
4. Attach the accessory you will be using to the
receiver extension.
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