Hi i'm not sure how this website works but as far as i know it's to get other opinions and help with car problems. Well ok i have a Chevy Tahoe 07 5.3 in having problem with the fan staying on. So this i noticed started to happen after i had to change the water pump due to a bad pulley there at that same time i changed the thermostat. After that is when i noticed the fan once my car is warmed up i start driving it stays on won't turn off as it normally should. I replaced the thermostat because i thought maybe it's that. Well the fan still stays on idk why. And the fan makes a loud obviously not normal noise like humming or like a blow dryer sound that's how I can explain it. Anyways hopefully maybe i can get good opinions or help to my issue here. Thank you
Yup, that's how this forum works. And, there is also a lot of historical information here from people who've had the same problems you're describing and successfully resolved them with the help of others here.
In your case, I suspect that you have either 1/ A bad coolant temperature sensor (you would also have strange indications on the coolant temp gauge in the dash or 2/ Still have air pockets in the cooling system after changing the water pump.
The coolant temperature sensor is cheap and easy to replace. It's on the outside of the driver's side cylinder head near the front of the engine. You can get a replacement at almost any local auto parts store. Most ship with the pigtail because damaged wires are common near the sensor.
If you have air in the cooling system, it will usually work itself out but you may have some luck, as I did, parking it on a hill with the front of the truck facing uphill and letting it sit for a few hours. Then fill the coolant reservoir to the line with clean 50/50 Dexcool, keeping an eye on the coolant level as you drive it over several days.