Under the dash on the right side just above the toes of the passenger's right foot.
The heater/AC fan has no relay just a switch. The Radiator fan relay is mounted next to the battery. It has 2 plugs and starts based on radiator temp and AC pressure.
by changing it.
you do not have a relay for a fan belt. just change them.
take it to a garage and get if fixed
use a piece of duct tape and wrap the clutch assembly
1 engine cooling fan and 1 heater/ac blower fan
If you don't have power to your heater or ac fan, it could be a fuse or a relay. You should check your owner's manual to determine which fuse or relay affects your fan.
Check and change the relay
Replace the heater/airconditioner fan relay. See other Q & A regarding heater fan running when ignition/engine off. A real pain--drains battery quickly.
First check your fuse if it is good then disconect the plug at the fan motor and check if it has power going to the fan, make sure the key is on and the heater is turned on. If you have power at the conector than you have a bad blower motor, if the fuse is good and you dont have any power to the motor then you have a break in the wire.
Need make, model and year of car.