Technical Temperature sensor broken?

[RolandH2O]

My fiat panda 100 HP from 2007 has a cooling problem when driving in a traffic jam.
The temperature reading climbs to red hot and only comes down by turning on the interior heating on max.
The cooler fan is not starting when temperature is above 90 degrees and the airco is switched on.
The radiator cooling fan works when connected to 12 volt directly.
When the temperature sensor is disconnected the radiator cooling fan is running.
So replacing the temperature sensor whill fix the problem?
Thanks for replying.

 

[koalar]

Temperature gauge runs off the same sensor
If the gauge is right I suspect the sensor will be tight

The aircon models have a two speed fan

If speed one isn't working it's usually the resistor module Part No 71740060

Although it has been rely, fan or fuse

If you have bidirctionl software you can activate the fan speed one and see if it's functioning, with the car stationary and the Aircon on it should be on a fair bit

 

[RolandH2O]

So if the temperature reading in dashboard works the sensor that controls the cooling fan is ok?
The resistor module is the device that controls the two fan speeds? So there are two resistors?
The fan motor / relais / fuse are ok.
How do i check the resistors?
Thanks a lot for co- thinking for be able to drive my hobby panda.

 

[koalar]

One way is use something like multiecuscan

And use it to.activate the fan at speed one and speed two

You can measure the voltage at the fan and follow it back voltage to the resistor and very low out would be a faulty resistor where as voltage to and similar out would be a break in the wire, something like 8V at the fan would indicate a faulty fan.

Another way is to jumper the resistor connector to test the circuit

If the fan then operates normally but at speed 2 it would be something like 95% chance it just the resistor

We would know all the wiring and ECU control's were working fine

There is no easy to measure the restance 0.27-0.3 ohms accurately enough as it so low, you could measure the voltage drop but sorry I don't know what the correct values are I would guess around 7.5V to 9.5V would sound about right

 

[RolandH2O]

I orderd a new resistor. The fuse on the old one was broken. The readings on the resistor jumped from zero to max also it was very crusty. I will share my findings when i replaced the resistor. Thanks Koalar , you're very helpfull.

 

[RolandH2O]

Problem solved! A new resistor did the trick.