Questioni have a 2003 envoy and i was wondering how to install a head unit because the stock radio broke..what wiring harness's would i buy and whats the approx. price?
AnswerHi Josh,
The answer depends on whether your Envoy is equipped with a factory Bose audio system, an Onstar system, or both.
In short, the factory radio in the Envoy controls some other vehicle functions. Most notably, all audible warning chimes are generated by the factory radio and play through the driver's door speaker. Also, the radio itself is controlled by the vehicle's computer data bus, so there's no accessory power wire in the factory radio harness.
If you want to keep the warning chimes working you'll need to purchase a data bus adapter module. This will also simplify the installation, because the module will generate a 12v accessory power source for the after-market radio.
If your Envoy is equipped with a Bose audio system, then you'll need a Metra GMOS-04 adapter to install the new head unit. This will work with or without the Onstar system.
If you don't have the Bose system, but do have Onstar, you'll need a GMOS-01. This also applies if you do have a Bose system, but plan to install new speakers and/or amplifiers so that you'll be bypassing the Bose amplifier.
If you don't have Bose, and don't have Onstar (or don't plan to use it) then the GMOS-01 will still work; but you can also use a GMRC-01. The GMRC-01 might be less expensive, but the GMOS-01 may be easier to find.
If you don't have Bose or Onstar, and don't mind losing the warning chimes and doing a little extra wiring, then you can purchase a Metra 70-2003 wire harness. This is the least expensive option, but it won't work if you have a Bose system or Onstar.
In addition to the adapter module (or wire harness), you'll need a radio mounting kit (Metra 99-2003) and an antenna adapter (40-GM10).
Similar parts are available from other manufacturers like Scosche, American International, Peripheral Electronics and others. I chose Metra parts because they're the ones used most commonly in car audio shops, and should be easy to find. You may find them under the brand name Axxess also; they're still made by Metra.
As for pricing, the adapter modules can usually be found for between $70 and $100. The wire harness and mounting kit will probably be between $10 and $25, and the antenna adapter will be between $5 and $15. The price in local shops will tend toward the high end of the scale, and the best deals will probably be found at online vendors.
The mounting kit should include instructions for taking your dash apart and removing the old radio.
Hope this helps!
Brian
