Why Sound does not work with after market CD player in 2005 equinox?

If the sound does not work with an aftermarket CD player in a 2005 Equinox, it could be due to several factors. One common issue is that the factory amplifier may not be compatible with the new unit, requiring a wiring harness or adapter to connect properly. Additionally, if the vehicle has a factory-installed premium sound system, the speaker wiring may differ from standard setups, leading to compatibility problems. Lastly, check all connections and fuses to ensure they are secure and functioning correctly.