I have a 2000 Honda Accord DX that keeps overheating recently I noticed that the cool/hot hand would go from normal to cool while driving but it never ran hot so I was told I had a bad thermostat so I brought a murray thermostat from o'reillys and now the car keeps overheating. I also replaced the temperature cooling sensor and the coolant sensor switch. I have checked everything there's no leaks the car has coolant in it. The water pump and all the hoses are good. The only thing now is the fan wont turn on unless you turn on the a/c and it wasn't like that before I replaced the thermostat. Help me please!!!!!!!!!!!!

 

Have you tried jumping the fan control switch? I only say that, since you mentioned the fans coming on when you turn the AC on, that means they still work, and it's in the control circuit. I think the switch is in the lower radiator tank. Either that, or it's screwed into the block.
You'll have to wait for someone more knowledgeable than I.

 

No I don't think they tried that yet but I will be sure to let them know. Thanks I appreciate your help and I will post the outcome

 

Parts drawing shows the fan switch still in in the thermostat housing. #15 in the picture.

Maybe 2001 or later they moved that??