Easy to install. Without cutting any OEM wire harness. The use of heat shrinkable tube connection has a better effect. Red wiring is not for all models, but if the OEM radio harness of your vehicle does not have an ignition wire, the aftermarket stereo cannot be turned off/on through the OEM radio harness. To solve this problem, you need to get a 12v power supply from the ignition by running the red cable separately from the factory radio harness. 2003 Envoy radio harness also fit for Pontiac Sunfire 2000-2005, Grand Am 2001-2005, Aztek 2001-2005, G6 2005-2009, Grand Prix 2004-2008, Montana 2000-2005, Montana SV6 2005-2006, Torrent 2006. Hummer SUT 2003-2007, H2 2003-2007, H3 2005-2010, H3T 2009-2010. Isuzu 2003 - 2008 Ascender. Oldsmobile 2001 - 2004 Alero, 2002 - 2004 Bravada, 2000 - 2004 Silhouette. Saturn 2005 - 2007 Relay. 2004 Savana stereo wiring replacement for GMC Envoy 2002-2009, Canyon 2005-2012, Savana 2003-2007,Sierra 2003-2005(DON'T FIT FORT 2005 Sierra 1500), Sierra Classic 2007, Yukon/Yukon XL 1500 2003-2006. Buick: 2004 - 2007 Ranier, 2005 - 2007 Terraza, 2005 - 2009 LaCrosse. The radio harness compatible with Chevrolet Cobalt 2005, Avalanche 2003-2006, Colorado 2008-2012, Corvette 2005-2013, Impala 2000-2002, Cavalier 2000-2003, 2005,Malibu 2001-2007, Malibu Classic 2004, Malibu Maxx 2004-2007, Monte Carlo 2000-2005, Silverado 2003-2004 (2007) Classic Models ONLY, SSR 2003-2006, Suburban 2003-2006, Tahoe 2004-2006, Trailblazer 2002, 2004-2007,2009 Uplander 2005, 2006, 2008 (No compatible with 2006 Silverado LT, 2004 Chevrolet express van). 2003 Cavalier car stereo radio wiring harness is not compatible with amp systems like Bose, Infinity, etc.