My fans are on all the time once the car reaches full temp. It never over heats or anything but should the one fan be running all the time? It has a new water pump from the dealer and runs great. Coolant has been flushed but I think they put a new thermastat in it. Should I get a 160 thermastat? Any idea's?

 

Is the SES light on? Have you scanned it for codes? Some codes turn the fans on to protect the engine.

Is your A/C or defroster turned on? The fans will run on low speed if it is.

Check the coolant temp sensor in the water pump. Courtesy of Shoebox:

http://shbox.com/1/4th_gen_tech2.html#ect

Or simply use a scanner to see what that coolant temp sensor is reading.

 

No codes and no light. It runs fine. It started happening after my water pump was replaced. I think the changed the switch or something from what was originally in it. It stays off until full operating temp then stays on.

 

What "switch"?

The PCM uses the signal from the temp sensor in the water pump housing. There is no "switch" unless you installed an aftermarket switch, but you would have mentioned that in your original post. That's why I mentioned that you should check the temp sensor.