Temperture My temperture thing, which lets me know what the temperature is outside, is not working in my 2002 Toyota Camry. What can I do?

Or you have a faulty thermostat. The thermostat may not be allowing the engine to reach operating temperature if stuck open or leaks keeping it in open loop. This will affect fuel milage. If the wiring to the sensor is good replace the thermostat and ensure the coolant level is correct and that ther is no air in the system after servicing.

Sure the engine coolant will be warmer than the outside temperture and if the car has been sitting a long time in cold weather and the outside temperture warms up it could be the other way around. The coolant temperture sensers aren't real accurate as they are a relaitive senser beween hot and cold and the numbers reported don't have to be real just the change from hot to cold and the reching of the coolant to the operating temperture. Noe it the senser doesn't read the opertating temperture coprrectly you'll have all kinds of problems. The therostaste will try to set the temperture of the water to it's set temperture and can open or close completly to get 195 degrees F. Many times if it's too cold then the stat is bad and needs to be replaced This shows up in alot of cars first thing after winter and the first onset of cold weather when the daily tempertures vary the most from day to night.

go to parts store online like autozone etc. and look for temp sending unit should take a 22mm wrench to remove not to difficult its located usually in the tstat housing

Defective coolant temperature sensor if it reads hot as soon as you start the engine. Check the wiring before replacing. The gauge itself can also be bad but not likely. The temperature sensor will look like this.

The temperature gauge sensor is what you need to replace. It is also a good idea to replace the thermostat, but is not necessary.
The sensor is usually located on the top of the engine on the driver side. It will (should) have a single wire coming out of the top of it.
Locate (purchase) a repair manual or ask a parts dealer representative to help locate it's exact location.
Please let me know if you need further assistance.
carsandcomps,
Guru, Premium Expert @ Fixya.com

Your manual should help, if not check with the dealer's service department.

you can't reset it. Try replacing the sensor.

SECTION 412-04: Control Components 2002 Explorer/Mountaineer Workshop Manual
REMOVAL AND INSTALLATION Ambient Air Temperature Sensor Removal and Installation

1. Remove the radiator grille. For additional information, refer to Section 501-08 .

1. Remove the three upper pin-type retainers in the radiator air deflector.

1. Position forward the air deflector.

1. Remove the ambient air temperature sensor.
   1. Detach the pin-type retainer.
   1. Disconnect the electrical connector.
   • Remove the ambient air temperature sensor.

Try replacing the magenetic clutch relay this relay is located under the hood in a junction block next to the battery.
The relay is labeled MG CLT.
Make sure the comp is pluged in and the belt is tight.

I also recently bought a 2002. According to the owner's manual the blue light does not indicate a problem unless it stays on after the car warms up. If you have an automatic it will not shift into fourth gear until the coolant warms up at which time the light should go off. Have only had the car for a week and notice the blue light goes off after a mile or two of driving in temperatures in the teens to 30's. I don't know how much outside temp affects it.

First of all, it doesn't sound like your thermostat is working correctly to keep good hot/warm air coming , so I would change that, or have it changed for better heating inside. If you lift the hood & look in front of your radiator, On the engine side, you'll see a fan attached to, or in front of the radiator. It won't come on until the coolant temperature gauge gets up to proper operating temperature. Without getting in to too much detail, have your thermostat changed, and my guess is everything else will start working as it should, and whoever does the work, should know enough to check the fan operation when they do the thermostat.