1999 honda accord ac / heater fan control

There could be a few potential causes for this issue. One possibility is that the motor for the fan is worn out or faulty, causing it to cut off at the highest speed. Another possibility is that there is an issue with the electrical connection or the fan control module.
Here are a few steps you can take to troubleshoot and potentially resolve the issue:

1. Check the fuse: Locate the fuse box in your car and check if the fuse related to the fan or HVAC system is blown. Replace it if necessary.
2. Inspect the fan motor: Open the hood and locate the fan motor. Visually inspect it for any signs of damage or wear. If you notice any issues, such as a broken fan blade or worn-out motor, it may need to be replaced.
3. Test the motor: Disconnect the electrical connector from the fan motor. With the car turned on, use a multimeter to test if there is power going to the motor when the fan is set to the highest speed. If there is power, but the fan still cuts off, the motor may need to be replaced.
4. Check the fan control module: The fan control module is responsible for regulating the fan speed. It is typically located near the fan motor. Check for any signs of damage or loose connections. If necessary, replace the control module.

If you are unsure or uncomfortable performing these steps yourself, it is recommended to consult a professional mechanic who can diagnose and fix the issue with your AC/heater fan.

Is the air blowing out of the defrost or heater vents? My thought is it has to be going somewhere if the blower is on, so it would likely be a faulty climate control unit or blend door motor shifting it to the incorrect position. If I can assist further, reach me at https://www.6ya.com/thericepatch

Sounds like high blower relay is bad

No heat could be the heater core is plugged and needs flushing out. Or the control that opens the valve is not working. --- No AC could be the drive belt is broken or the AC clutch quit or the freon is low in the system.

Sounds like the Blower Motor Resistor. The range from 10 to 75 dollars depending on what kind of vehicle. Pretty easy to change.
Blower Motor Resistor Repair Heater Fan Speed Control Chevy Blazer GMC...

check the fan itself to see if it works. check the heater fuse first! if all is ok, you probably have a bad heater fan resistor. to check blower, please go here on pc for info on blower. .cargurus.com/Cars/Discussion-t16272_ds569146

New switch should do the trick

try changing the compressor relay

Is the coolant full ? Any discoloring of the coolant ,look like muddy water ? gm dexcool antifreeze if mixed with regular green coolant can gum up the works , clog heater cores , radiators etc.... Have you ever had the thermostat changed , cooling system flushed ?