2006 GMC Envoy I6 HVAC fan stopped working. Level 5 stopped about 6-months ago and now it doesn't work at all. I checked all fuses and the cooling fan relay but still not working.

Question edited for clarity.
Question moved to model category.

Here are all your fuses

GMC Envoy (2002-2009) fuses and relays

https://fuse-box.info > gmc > gmc-envoy-2002-2009-f...

Here you will find fuse box diagrams of GMC Envoy 2002, 2003, 2004, 2005, 2006, 2007, 2008 and 2009, get information about the location of the fuse panels ...

GMC Envoy problems and GMC Envoy repair histories -- car repair descriptions reported ... by car, to see how many repairs each car required and where the car is located. ... 5.3L V8; 2006 291-horsepower 4.2L I6; 2005 275-horsepower 4.2L I6; 2004 ... Advised by OnStar not to drive and have it towed. ----------------------------------------------
galletto 1260

each fan also has a relay ,, check that

{: ) Check the underhood fuse labelled BLWR (40amp). Check the rear fuseblock fuses labelled HVAC (20amp), HVAC1 (10amp), and HVACB (10amp).
The next most common cause is a faulty blower resistor.
You may also have a malfunctioning blower; it could be stuck, or open circuited, or the connectors are faulty. The HVAC controller is also a possible culprit, although it seldom happens.

you may wanna check your fuses our relays you could find further instructions on your manual

Check for the fuse box that contains ECU fuses, good chances are atleast one fuse is bad.

I doubt there is a common cause. The rear HVAC needs to be diagnosed by a HVAC technician. The electric windows problem is probably a bad motor in the door. Do the rear windows work from the driver's controls? If they do, then it is the window switch that is faulty.

{: ) The popping sound you heard is caused by the sudden movement of an HVAC door, most probably coming from the recirculation door actuator (right dashboard area) or the mode actuator( mid dashboard area). The fan outputs could be normally working, but is being muffled by the incorrect positioning of the HVAC doors, giving an impression that there is fault in the blower controls. In other words, your vehicle is having an air distribution issue.
If there's no conflict in your climate settings, then the trouble may be in the HVAC doors binding or broken, or the actuators faulty or sticking. In both cases, servicing may involve removal of the dashboard to access these HVAC components.

Check your ignition switch by checking the voltage at the fuses for affected circuts vs. other circuts that are working well...

There is a Sending Unit for the Gas Guage Under the Dash I Believe. It usually Runs about $750.00 Just for the Unit. I agree with you!