4 days ago my wife said the car made a lot of steam. After that, we are loosing water and over heating.

I have found a failed radiator fan switch. Switch would never close to activate fans.

Could this alone cause my problems? I am (tomorrow) changing the switch, thermostat, and radiator cap.

Any other suggestions?

 

Yes a Failed fan switch would cause the fans never to come on, which in turn would cause overheating, at idle or a stop. this is a huge issue when the vehicle is in stop and go traffic opposed to freeway driving its very likely to never overheat even if the fans are not coming on, using 60 mph against the radiator to be sufficient enough air flow for cooling purposes

 

more then likely your thermostat and radiator cap are fine but replace them for preventative maintenance ..... If you are damn sure your switch is bad, a bad cap would cause you to over heat.... a cap's purpose is to apply pressure to the cooling system higher pressure >> higher boiling temp. What did you do to condemn your fan switch.... did you check the circuit starting with Fuses, relays, and so forth? But.... saying that these switches are popular to go out ,.... my did, and have seen alot do the same..... lastly a stuck closed thermostat would do it as well..... like i said, what makes you think the fan switch is bad? Did you run the car at idle and observe the engine fans to make sure they were not coming on?

 

Yes, have voltage to relays, jumping contacts the fans come on. Removing the sensor connector and jumping those two wires the fans come on. Everything in circuit tested except sensor.

Ran at idle till temp was at 206 in radiator, fans never came on. Book says 196 to 203 switch should close.

 

Over Heat is history. New thermastat, fan switch, radiator cap, holding temp very stable now.