- Proximity to radio towers, airports, police and fire towers
- Installation of some aftermarket accessories
- The presence of fluorescent lighting
- Some brands of radar detectors, CB radios, walkie-talkies, mobile radios, and cell phone chargers. These devices may be in the affected vehicle or may be in another vehicle in close proximity
- High RF traffic areas, such as shopping malls or stores with automatic doors or other RF devices
- Line of sight; the transmitter signal may simply be obstructed by another vehicle, a building or other obstructions
FYI: We are selling the Santronics Keyless Entry tester pictured in fig 2. It is identical in design to the SPX Kentmore Tester that GM dealers use. The only difference is that since it is not branded with the SPX Kentmore logo it is a whole lot cheaper.