Blower motor on my 04 silverado will not turn off . even when key is off . if i pull fuse it will work normal when key is on .if i pull out the air con. heater control nobs and controls and put fuse back in the blower runs. it started when i used the air conditioning

Question edited for clarity.
Question moved to model category.

Seems to be a known issue.

Blower Wont Shut Off - 1999-2013 Silverado & Sierra 1500

GM-Trucks.com https://www.gm-trucks.com > forums > topic > 11348...
May 9, 2010 - If the blower resistor is shorting prematurely then you most likely need a blower motor due to excess current draw.

Chevrolet Silverado 2007-2013: Why Won't My Blower Work?

ChevroletForum https://www.chevroletforum.com > how-tos > chevrole...
Another common problem will be the blower motor will stick in the ON position and never shut off.

Blower Motor Won't shut off ' GMC Truck Forum

gmfullsize.com https://www.gmfullsize.com > ... > Maintenance
Jan 17, 2011 - While driving today blower motor Kicked out, I turned up the fan speed and it kicked back in. Got to my destination, turned off the key and the ...

Missing: Classic. ‎' Show results with: Classic.

Heater/blower Won't Shut Off - Ask the GM Technician

GM-Trucks.com https://www.gm-trucks.com > forums > topic > 72853-...
Jan 11, 2008 - Cause is a mis-positioned harness from the blower motor assembly to the right I/P fuse block C4 causing harness rub through at right I/P metal ...

Have you checked to see if the blower relay is stuck on ?

I doubt its a relay.
The high blower relay only comes into play on the high setting. You have a 40amp fuse for the blower relay, then a 30amp fuse for the other speeds. The 30amp fuse powers the fan switch, when you turn it to high it activates the high speed relay.
I would check for power at the blower motor on all speeds.

I guess the answer would be maybe.
There is a blower motor control processor and a HVAC control module on the dash. The processor controls the blower motor.
Either component could power and ground the motor.

Turn the key on and make sure the blower motor is working. It doesn't matter what speed. Turn the key off. Pull the hvac1 fuse out of the under hood fuse box. Wait five minutes. Reinstall the fuse. Turn the key on, do not start the engine or touch the heater controls. You should hear the heat swiping through the different modes. After a couple of minutes it should stop. Turn the key off then start the vehicle. It may take several tries but eventually it should recalibrate.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

The switch doesnt "power the resistor" it GROUNDS it. I dont have a diagram here at home, but how about the wires at the blower motor.If both are hot, theres a bad ground somewhere. Did it act up before it didnt work? So is it a VAN or a truck? 04 or 01?

CHECK HVAC FUSE OR BLOWER MOTOR RELAY/FUSE.IF BOTH GOOD BLOWER MOTOR BAD OR CONTROL SWITCH GOING BAD.IF YOU HAVE TO REMOVE BLOWER MOTOR HOTWIRE TEST IT BEFORE BUYING ANOTHER ONE.BE SURE TO DISARM AIR BAGS SYSTEM WHEN WORKING AROUND DASH OR STEERING AREA.REMOVE AIR BAG FUSES TO DISARM.WAIT 10 MINUTES.WHEN YOU GET READY TO ARM AIR BAG PLACE FUSE IN.TURN ON IGNITION THE AIR BAG LIGHT WILL FLASH 7 TIMES THEN TURN OFF.

you will need to replace the blower motor AND resistor. It may need more. but start by checking all fuses.

you need to check the blower motor resistor.

You will need a Blower motor resistor and maybe a blower motor resistor connector end. If you look under the dash on the passenger side(may need to remove smooth black cover, vents will be sticking out) you will see a connector going straight up into the blower motor resistor(7 wires/slightly in front of blower motor). Pull out the connector and check for melted terminals/wires. If no melted terminals just replace blower motor resistor with part # 89019088 per GM to revert to part before 04 in order to stop blower motor resistor relay from hanging. Let me know if i can help more.