more than likely the blower motor resistor is out. it uses resistors to reduce the voltage sent to the fan to make it spin slower when the resistors go out on low and med your are left with high witch is battery voltage 12v.
Blower resistor needs replacementRelay for low speeds needs replacementBlow motor needs replacement (one of the 2 windings burned out)
If your Ford E-250 blower isn't blowing on high, it could be due to a faulty blower motor resistor, which regulates the fan speed. A blown fuse or a bad connection in the wiring could also be responsible. Additionally, the blower motor itself might be failing. It's best to have these components checked to determine the exact issue.
more than likely will be the blower motor resistor has went out.
If the blower runs on high it will get hot. If the blower is wearing out this will cause it to get to hot and blow.
Green with black stripe
Check the blower motor put the fan on and see if it blows on high if it doesn't replace the blower motor if it does blow high replace switch
Replace the high speed relay.
The blower motor resistor is defective.
needs new blower resistor
More than likely the blower motor speed resistor burned out.
bad blower,buy a good one and replace
Blower Motor Resistor is bad. 20.00 part at AZ.