Here's where you should look, in addition to under the dash:
* Behind the kick panel: On the driver's side, remove the kick panel (the plastic panel at the bottom of the dash, near your feet). The harness might be tucked away here, often secured with zip ties.
* Behind the glove box: Less common, but worth checking. Remove the glove box to access the area behind it.
* Near the fuse box: The harness might run near the under-hood fuse box or an interior fuse box, but typically not directly *in* the fuse box itself.
* Along the firewall: Follow the path of the wiring from the 7-pin connector at the back of the vehicle toward the front. You might find the brake controller tap point somewhere along the firewall.
* Consult a wiring diagram: A wiring diagram specific to your 2006 GMC Envoy will show the exact routing of the trailer wiring harness. You can often find these diagrams online (through repair manuals or forums dedicated to your vehicle). This is your best bet for pinpoint accuracy.
If you can't find it visually:
* Use a test light or multimeter: Start at the 7-pin connector and trace the wires associated with brake control. A multimeter can help identify the correct wires with a continuity test, following their path.
Important Considerations:
* Professional Installation: If you're not comfortable with automotive electrical work, it's best to have a professional install the brake controller. Incorrect wiring can damage your vehicle's electrical system.
* Aftermarket Kits: Many aftermarket brake controller kits come with detailed instructions, but even these sometimes require some troubleshooting to locate the correct wiring.
Remember safety first! Disconnect your vehicle's negative battery terminal before working on any electrical components.
