1999 Chevrolet Astro Owner's Manual - Page 124

yellowblue Operating the Transmitter Press and hold the appropriate button on the universal transmitter. The indicator light comes on while the signal is being transmitted. If the hand-held transmitter appears to program the universal transmitter but does not open your garage door, and if the garage door opener was manufactured after 1996, the garage door opener may have a "rolling code" system. A rolling code system changes the code of the garage door opener every time you open or close the garage door. To determine if you have this system, press the button on the universal transmitter that you have programmed already. If the indicator light flashes rapidly for one to two seconds, then turns solid, the garage door opener has a rolling code system. In a rolling code system, the garage door motor head unit must be trained to the universal transmitter. Training a Garage Door Opener with a "Rolling Code" Feature (If Equipped) If you have not previously programmed the hand-held transmitter to the universal transmitter, see "Programming the Transmitter" listed previously. If you have completed this programming already, you now need to train the garage door opener motor head unit to recognize the universal transmitter. Refer to your garage door opener owner's manual for the proper transmitter training procedure for your garage door opener brand. 1. Find the training button on the garage door opener motor head unit. The exact location and color will vary by garage door opener brand. If you have difficulty finding the training button, refer to your garage door opener owner's manual. 2-54