Blower motor will not work. Done checked all fuse boxes I can find also replaced blower motor and relay box that is between blower motor and switch. Are there any other areas I might be overlooking

I looked at 05 avalanche 1500--automatic hvac. The blower fuse is hot all the time. The fuse has an input leg and output leg, even if the fuse is blown, the input leg would still have voltage. If no voltage, you could use jumper wire connected to voltage on the output side of fuse cavity to see if blower would work. If you use jumper, use an inline fuse.
Yes, it could be something wrong with fuse box or wiring circuit?

F4 30 amp under hood fuse box , F45 5amp - smart junction box ( passenger compartment fuse box ) right or left kick panel probably . Also ,there is a blower motor relay - under hood fuse box. You can check those but don't think it would be one of those . More then likely it's the blower motor speed controller .

Check fuse #14 (10A) in the under dash fuse box (drivers' side).

Check the blower motor relay in the underhood fuse box. to check it, simply switch it with another identical relay. If the blower now works the relay is bad.

Smack it and see if it comes on. If it does then the motor brushes are bad. If it does not come on, check the fuses. If the fuses are ok, check the voltage on the plug to the motor.

Four possibilities. One is the blower motor fuse in the fuse box to the left of the steering column. One is the fan switch on the dash, One is the ballast resistor under the dash below the glove box. Third is the blower motor itself. The first three take a few minutes to check out. Replacing the blower motor requires an hour and a half if it's done by someone who's done it before. I've replaced a dozen of these.
Good luck

CHECK HEATER AND AC IGNITION 10 AMP FUSE UNDER HOOD JUNCTION BOX.IF ALL IS GOOD CHECK BLOWER MOTOR FUSE AND RELAY.IF ALL LOOKS GOOD. TURN ON CONTROL SWITCH TO CHECK TO SEE IF POWER GOING TO BLOWER MOTOR IF YES BLOWER MOTOR BAD.IF NO POWER GOING TO BLOWER MOTOR FUSE AND RELAY GOOD.YOU HAVE BROKE WIRE BETWEEN SWITCH AND BLOWER MOTOR OR CONTROL SWITCH FAULTY. TO GET TO BLOWER MOTOR ITS LOCATED UNDER THE DASH ON PASSENGER BEHIND GLOVE COMPARTMONT YOU DONT HAVE TO REMOVE GLOVE BOX ITS JUST BELOW IT FAR BACK.YOU NEED TURN OFF RADIO FIRST THEN DISCONNECT NEGATIVE BATTERY CABLE WAIT 20 MINUTES THIS DISABLE AIRBAGS AND THE BCM.REMOVE BLOWER MOTOR HOTWIRE IT TO SEE IF ITS WORKS. IF NO BLOWER MOTOR NO GOOD.IF BLOWER MOTOR GOOD THE AC AND HTR CONTROL SWITCH IS BAD DEALERSHIP FIX.

This may be a faulty Blower motor resistor, usually mounted inside the blower motor air box, or defective blower motor. There is no single Relay for the blower motor.

Step 1: Check fuse
Step 2: Change relay (usually can swap with another relay in the fuse box and try it)
Step 3: Check connection on switch
Step 4: Replace Switch
Step 5: Check connection on blower motor
Step 6: Replace blower motor

Chevrolet has a bad reputation for the connection and/or switch malfunction for the blower motor. I changed all 6 items in my truck in a 3 month span as all 6 appeared one right after the other.
Good luck.

C-19 Blower motor fuse 25A located in cabin fuse box. Left hand footwell on LHD vehicles, right hand dashboard on RHD vehicles.
Start by checking blower relay B-36 in the engine compartment fuse and relay box. Remove the relay. Jumper directly from battery to pins 85 and 86. (also see here: http://www.fixya.com/cars/r5544622-wire_relay if you dont know about relays) The relay should click Now measure across pins 30 and 87. Measurement should be 0 ohm.
Remove the blower motor(3 screws on the bottom of the unit under the passenger side dash) and connect jumper leads from the battery directly to the blower motor to see that it operates.
The blower motor resister is mounted on the ducting between the motor housing and the heating unit. Remove to test
Measure :

• pin 1-2 : 2.4 ohm
• pin 2-4 : 0.9 ohm
• pin 2-6 : 0.28 ohm
• pin 2-3 : 0 ohm

1. Does the Blower work on High (or #4) only? If so then it is not the Front Blower Motor or the Relay that is bad, but it is the Resistor which is located behind the Glove box. Follow step #a. below and take out the Glove Box to access. It has 3 to 4 wires going into it. The wiring path is: Switches to the Resistor and then to the Motor.
2. The Front Blower Motor Relay is located in the IPM - Fuse and Relay Center. It is located in a box within the engine compartment. However: (restated) IF the Blower does only work on High then this Relay is good and you should only replace the Resistor Only. The Identification and Location of the Relays and Fuses is located on the back side (inside) of the IPM cover. Remove the cover. The Front Blower Motor Relay is the same Type (size and shape) as several other Relays in the panel. Switch out the Front Blower Motor Relay with a non-engine operation Relay for a function that you know works. Recheck the operations of both functions. If the Front Blower Relay now works and the other function now does not work, it was the Relay was bad and needs to be replaced.
a. Disconnect the Negative Cable from the Battery and wait at least two (2) minutes to deactivate the Airbag Sensors.
b. Remove the Glove Box.
c. Disconnect the Electrical Connection.
d. Unbolt/Unscrew the bolts/metal screws and remove the Resistor.
Installation is reverse of above.
Let me know if this helped, or if you have additional information or questions. Feel free to contact me at FixYa.com!