Two problems related to turn signal flasher unit have been reported for the 2004 GMC Envoy. The most recently reported issues are listed below.
When right directional signal was actuated, intermittently would also activate hazard (4-way) flashers. Dealer replaced flasher module (ref TSB 30842014) and has been ok since then.
2004 GMC Envoy developed the following problems: vehicle stalled, turn signals stopped working, blower fan stopped working, and the srs light remains lit. The turn siganls stopped working due to a short in the flasher. The powertrain control module was replaced due to the ses light iluminating. The blower motor fan failed 4 times due to a short in the wires and control head. The vehicle overheated, but the problem could not be diagnosed. The lcd displays, knobs become extremly hot after hours of driving.