you probably have a leaking heater core....you can replace it or bypass it
Did you happen to move it to Defrost when you turned it off? The ac compressor also runs in the defrost cycle to keep the seals lubricated during the winter months when the ac is not used.
It is overdue to be changed.
when the defroster is turned on, it activates the a/c compressor. the clutch may be locking up on the compressor.
Perhaps you turned on a button for it. Or there may be a problem with the oil and you should take it in to get checked.
Check Your Waterpump
You should be able to hear it when the car is turned on and turned off, even if the antenna is broken off or stuck and won't go up or down.
The A/C system compressor operates when in the defrost mode. If the noise is also heard when running the A?C it is more than likely a problem with the compressor/pulley.
A bad thermostat can cause overheating in a Nissan Frontier when the air conditioning is turned on. A bad compressor can also cause this.
If the motor has not been turned over without the belt you should be able to put the new belt on where it is..
yes it is, there should be a button specifically for the headlights to the left of the steering wheel
If it is leaking antifreeze or water, or if it is making noise or binding when turned by hand.
Theres to much water in your reservoir bottle, theres a mark were it should be filled up to, any more and it will flow over.