Electrical malfunctions in 2006 GMC Envoy XL

You need to replace the BLOWER MOTOR CONTROL MODULE. its up under the dash, near the blower motor. Your dealer or a AC DELCO parts house will have it in stock, very common problem.

Why not save a lot of money and aggravation,
and just go down the street to a local repair shop?

Replace the blower control module near the blower motor.

{: ) 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.

does it work on heat mode if not then it is probably the blower motor switch in the dash or the blower itself

heve utried adjusting the trottle , just put your foot on the accelerater and hold at just under 1000 revs if shaking goes then thats your problem should idle at just under 1000rpm

Need to check to see if the blower motor is running.If it is,but not threw the vents,most likely a vent door actuator motor.The actuator motor in this case would be bad,it is hard to get to,unless you are mechanically inclined,You can do it your self.If the blower motor is bad,just replace it.Check fuses first,and the blower relay.If I can help,let me know.

you will need to replace the fans blower resistor. its mounted in the cab. in the lower right side of the heater box. some aftermarket suppliers are carrying the part but all chevy or gmc dealers will have it.
good luck chris

one of the second heater core lines is clogged.

It's the blowe motor resistor real common