My electric fan isn't working and I replaced the fan and checked the leads which are hot going to the fan. what is the problem?

Check the fuse to the cooling fan if it's good then it could be a bad fan module either it's built into the fan itself or follow the wires from the fan and it should lead to a module. If all looks good and is getting power then replace the module which will be either a whole new electric fan or a fan module mounted somewhere up front near the fan

if the fan is electric, the problem is probably the fan thermostat. usually fitted into the water pipes near the radiator.

Physically look in the radiator under the cap for coolant level, and check the valve in the cap for sticking. If air is present in the radiator it can't get out, and more coolant can't get in,(from the overflow). Either clean the cap or replace it and check that it is the CORRECT cap.
Radiator fins dirty, clean with a strong stream of water, not high pressure water.
Radiator clogged, have it boiled out, or replace.
Thermostat stuck open or shut, replace it.
Water pump worn out, can no longer move enough coolant, replace it.
Fan shroud broken or missing....
Electric Fan(s) not working, Check the fan, relay, fuse and engine temperature sensor's.
Belt driven fan, belt slipping, fan clutch is bad, fan blades have flattened out.
Air dam under front bumper is gone, loose, or broken. It actually has a purpose other than scraping on the driveway or curbs. It forces air up into and thru the condenser and radiator. If it

A clogged radiator could be your problem. Flushing won't necessarily clean out a clogged radiator.
When it's idling and getting hot, the clutch fan should be running full on, actually "roaring" as some say, and the electric auxiliary fan or fans should be on if you have them. Also test your radiator cap, replace if needed. Hope this helps.

The electric radiator cooling fan isn't working, first check the fuse[s], then it's either the fan motor,or the sensor.

Sounds like perhaps the electric fans are not working. The fan(s) run only when the tempurature reaches a certain point. When you are sitting at a traffic light, you are not moving through the air and therfore you have no air moving through the radiator to cool the hot fluid inside the radiator. This is a situation where the electric fan would start up in order to cool the engine when there is no air movement otherwise.

Causes: No power --- check the fuse for the radiator fan and replace if blown. If it blows again then something more is wrong that needs to be diagnosed.

Temp sensor is no longer functioning --- Check the temp sensor for connectivity when hot (on some cars you can simply jump the switch and see if the fans run)

Fan(s) are bad --- Apply 12 volts to the fan power lead and see if they run. If they do then something else is blocking or not transfering the normal power to the fans, like a relay or control module. ( more diagnostics needed here)

It depends on how mechanically inclined you are. If you feel comfortable doing these kinds of tests then go for it. If not, perhaps a nice "good reputation" shop might be your best choice.

If you have further questions, just ask.

check the fusable link to the lead hot wire to the blower motor. it is embedded in the wiring and maybe blown

Thermostat

Test thermostat in a jug and pour boiling water on it , it should compress meaning it works. Check that the waterpunp is operating pushing water into the engine .Check that radiator water flows to the watrpump. Is tension of fanbelt of waterpump sufficient that it doenst slip. Lastly check that the radiator fan is working if has a electric fan. if this doesn’t help check if radiator or engine water passages isn’t blocked.

I'd make sure you have fluid in your radiator. Does you AC blow cold? If it doesn't there is a chance you are low or out of fluid. This would lead to a crack in the radiator. Is it a crank shaft driven fan of electric?