The antenna is embedded into the window glass.
CAUTION
When washing the inside of the window which has an antenna, use a soft cloth dampened in lukewarm water, gently wiping the antenna lines. Use of glass cleaning products could damage the antenna.
AntennaMazda 6 Owners Manual: Cargo compartment light switch inspection
1. Remove the liftgate lower trim. (See LIFTGATE LOWER TRIM
REMOVAL/INSTALLATION)
2. Disconnect the cargo compartment light switch connector.
3. Inspect for continuity between the cargo compartment light switch
terminals using an ohmmeter.
If not as specified, replace the liftgate lock.
...
Mazda 6 Owners Manual: Automatic transaxle removal/installation
1. Disconnect the negative battery cable.
2. Remove the battery and battery tray.
3. Remove the aircleaner component. (See INTAKE-AIR SYSTEM
REMOVAL/INSTALLATION.)
4. Remove the front tires and splash shield.
5. Remove the under cover.
6. Remove the steering gear and power steering pipe. (See ...