Is it my fan ?

when i am stopped at a redlight i would overheat from quarter under to quarter over half and even sometimes full top. but ones i start driving at a decent speed 70+ it will drop back to under half for awhile and then it would do the same thing over and over and over

how do itell if my fan is working i havent heard it spin but i havnet been paying attention

but if its not the fan what could it be going up and down up and down

 

What you can do is open up the hood and see if the fan is working, that'd be a good start. Check your coolant level and also check your thermostat and hoses for problems.

 

What car do you have?
a ghetto way to check your fan is unplug it and use some jumper wires and jumper it to the battery and see if the bad boy spins up. If it doesn't then your fan is shot. If it does then you know it's good, but maybe the wiring circuit to the fan is bad. To check that, plug it back in and start your car. Let it warm up in your driveway and if it starts to over heat and the fan doesn't turn on then you know it's something in the circuit.
Did you check your fan's fuse?

 

i would check your fan operation and check the thermostat.