Fan doesn't run while in idle and begins to over heat until I start driving agin then it cools back down to normal. Also the fan runs when engine is off and drains the battery.

Over heating the engine is a serious concern. With the hood raised you should hear the motorized fan turn on just behind the radiator as the engine requires additional cooling.. If you look in from the rear of the radiator you should see the fan blades.

This electric powered motor operates on a thermostat and when the engine temperature rises this fan should come on. I'm assuming from your description that when driving and air is flowing through the radiator as the car travels the engine is nor overheating.

Check fan motor thermostat, check fan motor and check wiring.

Wiring Diagrams related to the Honda Civic
http://www.wiringdiagrams21.com/category/automotive/honda-automotive/civic

Motor engine cooling fan only runs as engine temperature requires additional cooling.

The most common reason for running hot at idle is the radiator fan is not running or pulling enough air thru the radiator. If you have a fan for the engine and one for the ac, the engine fan may not be working.
The radiator fan should come on when the coolant reaches 220 degrees. The computer sends a signal to the fan relay.

coolant temp sensor tells the computer how hot or cold the engine is so it can regulate the idle and fuel mixture, when it fails there usually is no cooling fan and you will have trouble starting the engine and keeping it running.

Check first your coolant level. Start engine and turn on ac open hood see if cooling fans are running, if fans are running and coolant level is ok temperature should stay normal. If temperature rises squeeze coolant hose, it should be firm like you could feel pressure on the hose a sign that the water pump is good. Thermostat opens only when coolant reach normal operating temperature.

is the car running hot? some cooling fans never come on going down the road because the air comjng through the front of the vehicle keeps the car cool enough that it doesn't need to come on. but if it is overheating then you may want to check the cooling fan relay.

At idling speed an engine does build up a lot of heat and the cooling fan will kick in. In slow moving traffic or traffic jams the temperature gauge can touch the red - particularly on hot days. The reason it cools down when you start moving is because of the air flow through the radiator.

Presumably there are no leaks from the cooling system otherwise you would have mentioned it. In normal circumstances the fan will not be running as you are driving at speed, as the air-flow through the radiator is sufficient to cool things. The fan only kicks in to get rid of excess heat - and this usually occurs at idling speed or after you have parked the car.

If the fan is running all the time as you drive, this points to either a fault in the fan switch, or the car is running too hot. presumably in normal driving the fan isn't running and the temperature gauge reads normal?

It is common - in stationary traffic many cars overheat (particularly big engined models) try to stall and 'cut out'. Restarting can be difficult until the engine cools down.

Is your car overheating in normal driving conditions or just at idle speed? Overheating in normal driving conditions can be caused by things like a failing water pump, blocked radiator, collapsed hose, faulty thermostat or, in the worst case scenario, cylinder head problems.

Overheating at idling speed is 'common'. Check your coolant level. If your car isn't using/losing coolant then there probably is no major problem. You can flush out the cooling system and refill with new coolant - and also check your radiator. Are the cooling fins crumbling with age? Or maybe they're partly clogged with insects and debris from the road? A blast with a hosepipe wil sort that out ..

The question is how much does your car overheat in normal driving? If it doesn't .. it appears as though you have nothing to worry about as such. Most cars have 2 speed fans... the 2nd faster stage kicks in at some point dependant on engine temperature. Perfectly normal.

This is perfectly natural for the fan to continue running when the motor is turned off. I have seen them run for up to 15 minutes depending on how hot the day and the engine are. If it is not cutting off at all then you may have a problem in your heat sensor.

You have two fan's on your truck, 1 is a fan clutch runs with the drive belt, 2 elec fan motor, with test light and engine running at normal temp, just a little bit above 1/2 way on your temp gauge check voltage at elec. cooling fan harness if you have voltage at one of the two wire's and fan don't turn on, bad cooling fan motor, on the fan clutch after you check voltage at elec. fan motor turn engine off, with your hand spin drive belt fan if it spin's freely bad fan clutch, replace it.Also check cooling level.Hope this was very helpful

Check the cooling fan switch. It appears your auxiliary electric cooling fan isn't going on when at idle. and engine temp increases. While you are driving, air is being rammed thru your radiator as you cruise along, so it isn't overheating, at idle, that isn't happening, and the fan should go on as the temp goes up. When the ac is switched on, the fan is being signaled to operate due to the heavy ac load on the cooling system.

check thermostat might be sticking or radiator may need flushing if it only heats up while idling check your electric fan may not be coming on try turning on the a/c the 2 cooling fans should come on then if they do then i would check the cooling fan switch if they do not come on when the a/c is switch on you may have a bad electric fan motor or wiring to the fan or fan relay