GMT800 Silverado Stereo Upgrade: Double DIN Swap, Wiring Harness, and What Fits the Dash

Upgrading the stereo in a 1999–2007 Silverado or Sierra is one of the best value mods you can do. The factory head unit is AM/FM only with no Bluetooth, no aux input, and no navigation. A double DIN swap fixes all of this.

WHAT FITS

  • GMT800 trucks have a double DIN dash opening — any standard 7" double DIN head unit fits
  • You need a dash kit to fill the gap around the head unit (Metra 95-3305 for most models)
  • A wiring harness adapter connects the factory plug to the aftermarket unit
  • Trucks with OnStar need an GMOS-LAN interface module to retain the OnStar system

HEAD UNIT OPTIONS

  • Pioneer DMH series — touch screen, wireless CarPlay/Android Auto, backup camera input
  • Kenwood DDX series — similar features, excellent sound processing
  • Sony XAV series — good value option with CarPlay support
  • Alpine iLX series — premium option with OEM-style integration

WIRING

  • Metra 70-1858 is the correct harness for 1999–2007 GM trucks
  • Connects factory plug to standard ISO connector on aftermarket head unit
  • Retains factory amp if equipped (Bose)
  • Add a Posi-Tap or Axxess GMOS-LAN if you want OnStar to keep working

BACKUP CAMERA

  • Most double DIN units have a reverse camera input
  • Run a camera to the license plate area — trigger wire connects to reverse light
  • Pairs perfectly with a new head unit for safety

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