My temp gauge says my car is overheating when im at a stop but running says its normal what is going on

Hi Bill, is the engine actually getting hot enough for the fans to come on? if the engine does have overheating problem (but you say the temp gauge reads normal) then i would check the operation of the engine temp switch, there are two, one for the gauge and one for the fans.

First check your coolant level. If it is low, look for leaks. Also don't rule out the reservoir isn't bad. Also if the hose is pinched to reservoir, this will cause low coolant in the engine.

Have you checked the temp sensor ? It could be faulty or there could be a wiring problem back to the gauge. Low coolant can cause an air pocket inside the system too.

Sounds like you have air in the system, try burbing the system , they make a special funnail for this procedure

Air pockets will make the guage do that, and also cause your heat to come and go. Also, a poor radiator, as in rotting, or plugged up, will cause high temperature issues.

the temp seems to be fine. 80degrees celsius or less in stop and go traffic is normal,especially since the cooling fans are working and coming on at the proper time. the what seems to be running rough is another problem that doesn't seem to related to the cooling system temp. may want to check the spark plugs for worn electrodes.

if you replace the temperature switch on your maxima your problem with the engine temp gauge will be fixed, as far as the clock.. im unsure about that.

they are designed not to fluctuate with engine temp and are kept stable once operating temp is reached. only if the temp exceeds a set mark will the needle rise to indicate overheating,

Replace thermostat. Then always make sure the fluid level is always kept up to the top of radiator.

The car is not overheating if the temp gauge goes up and down by turning the lights on and off.  The gauge is giving you bad information.   You can confirm this by starting the car from cold, sitting in the driveway, let the temp go to somewhere BEFORE normal operating temp, then turn on headlights and fan blower on high, watch the gauge, then turn them off.   If the gauge moves significantly from the electrical load, you probably have a short or a bad ground connection.  

You have a short circuit or bad wiring somewhere in the front half of the car.  I don't know what thermostat switch you have replaced ... but it's not the problem .. stop buying them.  
If you are the original owner, was there an accident that may have damaged some wiring?  If you bought the car second hand,  get a carfax and find out where the thing was hit ... concentrate your wiring trouble shooting in that area.

I think it is something OTHER than the temperature sending unit or the gauge