so i have problem with my camry. It over heats when in drive, i can run it in park for what seems to be forever but as soon as i put it in drive it jumps right up. The thermostat i believe to be working (i can feel flow through the tube) my radiator is full with the proper coolant as well as the reservoir...now what i believe to be my problem is the coolant fan. When i turn the A.C. on both fans mounted on the radiator will turn on, bringing my temp down. When i allow the car to heat up the coolant fan does not come on. I unplugged the wire harness doodad that connects the coolant fan to the engine coolant temp sens (ECT), turned the car back on and the fan was running like a champ. From what i understand, the ECT will have continuity when not hot and when it gets up to predetermined temp it will switch and have no continuity and turn the fan on. I figured when i unplugged the wire to the ECT this was acting as if the sensor was showing no continuity thus turning the fan on is my logic flawed? anyways i got a new ECT put it in the radiator, plugged the wire back into it turned the car on let it heat up and the fan still did not turn on, but both fans will still turn on when AC is turned on, does this sound like i may know the problem but got a bum replacement ECT?......PLEASE anyone help me solve this problem of how to get my fan back on track...oh yea i got the sensor from the dealership to and matches my old one exactly so i am pretty sure its the correct part

 

V6 or 4 cylinder? If V6 it may have more then one temp switch.

Your logic is correct.

The ECT switch should NOT have continuity when coolant temps are above 199F (approx).

Below 181F (approx), the switch should have continuity.

In between these temps ?

Typically if the engine is idling for long periods of time the fans will sooner or later start to cycle on and off, is this happening?

The Camry coolant system is more then adequate to cool the engine down when driving in other then stop and go traffic without the need of the fans. As such might check for issues with a plugged radiator, thermostat not fully opening, etc.

The fans normally are off when driving (moving above stop and go traffic) unless the A/C compressor is cycling.

 

it is a 4 cylinder so there is only one temp sens...is there any way to check to see if the radiator is plugged? i never thought of the thermostat not opening all the way, maybe ill throw a new one of those in there seeing how it did over heat once, i was told that this could compromise the thermostat