Toyota 2001 Tundra Owner's Manual page 166

Place the transmitter with Velcro square
facing inside of box into the box. Make
sure the transmitter button is located
above button pins.
'01 TUNDRA_U (L/O 0008)
Remove spacers from the center panel.
Place the largest spacer on the pin that
would be below transmitter button when
the cover is closed. Close the cover.
2001 TUNDRA (OM34416U)
When the garage door opener transmitter
is properly installed, you can operate the
transmitter by pushing the center panel of
the cover.
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