The Metra 70-1857 is a tuner bypass and Bose amplifier integration harness designed for select 1987–1996 Cadillac vehicles and 1990–1996 Chevrolet Corvette models equipped with factory Bose audio systems. This harness allows installation of an aftermarket radio while retaining the factory Bose amplifier system by bypassing the factory tuner module. It is one of the most commonly used solutions for upgrading older GM Bose-equipped vehicles that use remote-mounted tuner brains

Features & Highlights

  • Designed for select Bose-equipped GM vehicles
  • Bypasses factory tuner module (“tuner brain”)
  • Retains factory Bose amplifier system
  • Allows installation of aftermarket radio
  • Plug-and-play style integration
  • 204-inch extended-length harness
  • RCA input integration for amplified Bose systems
  • Supports factory speaker wiring retention
  • Compatible with modern multimedia radios including Apple CarPlay and Android Auto

Specifications

Specification Details
Product Type Bose Amp Integration Harness
Manufacturer Metra Electronics
Model Number 70-1857
Vehicle Compatibility Cadillac / Chevrolet Corvette
Vehicle Years 1987–1996
Audio System Compatibility Factory Bose Amplified
Harness Length 204 inches
Installation Type Tuner Bypass
RCA Connections Yes
Plug-and-Play Yes

Compatible Vehicle Applications

  • Cadillac Allanté (1987–1993)
  • Cadillac Brougham (1990–1992)
  • Cadillac DeVille (1994–1995)
  • Cadillac Eldorado (1992–1995)
  • Cadillac Fleetwood (1993–1995)
  • Cadillac Seville STS/SLS (1992–1995)
  • Chevrolet Corvette (1990–1996)

Important Installation Notes

  • Designed specifically for Bose-equipped vehicles
  • Blue amp turn-on wire MUST be connected for sound output
  • Factory tuner module is bypassed during installation
  • RCA outputs from aftermarket radio are required
  • Long harness length allows routing to remote tuner location
  • Professional installation recommended due to older GM Bose architecture

Works Great With

    Complementary products