GM Service Manual Online
For 1990-2009 cars only

The garage door opener (GDO) system effective range depends on several installation variables. Use the following guidelines in order to maximize the effective range. Plug the transformer into an available source of power on the receiver unit. After the receiver is installed, the owner should have no need to regularly access the receiver.

Important: Never mount the receiver unit out-of-doors. The receiver is not designed to withstand weather.

Mount the receiver unit so that no metal objects, especially metal garage doors, will be in the direct path of the transmitter signals as used from within the vehicle. Any metal object may redirect the signal away from the receiver. Many newer homes have metallic sheathing under the exterior finish. Mounting the receiver in an attic area should be considered if other mounting locations prove ineffective.

Mount the receiver as close as possible to where the transmitter will be used. For example, moving the receiver from the rear of a garage to the front may add 20 feet to the effective range. Do not place the unit behind any metal objects or out-of-doors.

When the guidelines listed above do not provide adequate range, extending the receiver antenna may provide additional improvements. Attach a wire to the receiver antenna in order to extend the antenna. Typically, 2 feet of a small gauge wire attached in a vertical position will improve the range.