my 65 impala heater worked for the last 5 years now all of a sudden it stopped

Did you check the power TO the switch or the power to the motor? If you checked the power to the motor, the next step is to check the resistors. They are somewhere in the plenum, close by the fan motor. There will be one for each speed of the fan switch, with one wire to each, and then one wire out from that to the motor itself. That is the normal reason for the fan to go south, unless the fan motor itself is dead. Pull the plug off the resistor pack, and check each individual lead using the fan switch to vary the speed selection. I would bet you have power from each lead. If so, plug the wires back into the resistors and then check for current OUT of the resistors. Chances are you will find none. If there is power out of the resistor pack, then you likely have a dead blower motor. If you do not have power out, then you need to replace the resistors. Good luck.

If your car has air conditioning there will also be a 30 amp fuse, in line, near the alternator. This is for high speed only. It won't effect the other speeds if it blows. Just high. HTH. -Jim