2001 Chevrolet Astro Owner's Manual - Page 138

If you have trouble programming the HomeLink Transmitter, make sure that you have followed the directions exactly as described and that the battery in the hand-held transmitter is not dead. If you still cannot program it, turn the hand-held transmitter end over end and try again. The HomeLink Transmitter may not work with older garage door openers that do not meet current Federal Consumer Safety Standards. If you cannot program the transmitter after repeated attempts, refer to "Training a Garage Door Opener with Rolling Codes" later in this section or contact the manufacturer of the unit at 1-800-355-3515. Be sure to keep the original hand-held transmitter in case you need to erase and reprogram the HomeLink Transmitter. Canadian Owners: During programming, the hand-held transmitter may automatically stop transmitting after one or two seconds. In this case, you should press the button on the hand-held transmitter about once a second without ever releasing the button on the HomeLink Transmitter. Release both buttons when the indicator light on the HomeLink Transmitter begins to flash rapidly. 2-59