thermosat could be stuck open or low coolant or heat control cable could be broken
pee on it
it could be your thermo stat
It could possibly be a clogged heater core
The air-condition belt on a 2001 Honda Accord also controls the heat. When the belt needs to be changed the ridges on the belt will show wear.
A block heater for a Honda Accord helps to quickly raise the temperature of the car to the proper heat level. This allows for a quicker engine start-ups.
radiator hose needs replacing. use and heat will cause hose to collapse when worn out
The air mix door is stuck in the heat position
Could be running backwards....reverse the leads and see if it stays cool running the opposite direction.
CHECK BLOWER MOTOR, AND HEATER CORE BOTH INSIDE THE CAR UNDER THE DASHBOARD