Car Temperature Gauge Stays on Cold and AC Not Working: What Are the Reasons?

reasons why car temperature guage stays on cold and ac not working

If your temperature gauge remains cold, there are several possible causes, including a faulty coolant temperature sensor, a stuck thermostat causing the engine to start improperly, or it could be faulty wiring between sensors or the cluster. Here are some technical reasons are given below that why your car’s temperature gauge Stays on cold:

Reason 1: The Engine Coolant Temperature Sensor is being faulty

One of the main reasons could be defective or damaged temperature coolant sensor that passes incorrect information to cluster which further becomes the reason why car temperature gauge stays on cold.

Commercial cars models can have one or two temperature sensors. The models having one sensor, use the same sensor for both the engine control unit’s temperature and the gauge.

Conversely, if the model has two sensors, one will be used for the engine’s control unit, and the temperature gauge will use the other one. It’s easy to measure the engine temperature sensors with a multimeter, you just have to look for the correct values as per your car model.

Reason 2: Damaged Wirings

Damaged Wirings can cause a car not to work ac

If your car has two sensors for measuring the temperature in which one is separated for the gauge, you need to check that it should connect with the sensor’s wire to the gauge.

But if your car has one sensor for both the measuring temperature and the gauge, then there could be some technical problems occur like wiring breakdown or burnout between the gauge and ECU (Electronic Control Unit).

To find the broken or wrong wiring, a multi-meter could check the resistance for all the wires’ directions.
For which you can check your car’s repair manual and look for the information regarding measurement of resistance correctly through your car’s wiring diagram.

Reason 3: Damaged or Defected Cluster/Gauge

Defected or damaged temperature gauge is also a problem. Mostly the temperature gauge is integrated with Cluster on the latest models, while in normal cases, you can repair the temperature gauge or replace it.

But a damaged or defective cluster is not a common problem because they are very expensive and need coding after replacing it as it is integrated with gauge. The cluster temperature gauge can be tested by an Ohm tester.

Reason 4: Corrosion of plugs or connectors

When we discuss a faulty temperature gauge, corrosion in plugs or connectors is one of the most common problems.

You can clean or spray the sensor’s connectors, the Cluster’s connectors, and the ECU’s connector to prevent this problem.

The problem with the connectors’ sealing can cause the problem of corrosion. You have to check them to make a permanent solution, either replace them to prevent further problems or repair them if possible and will not cause problems in the future.

Reason 5: Stuck Thermostat

Stuck Thermostat could be the reason Car Temperature Gauge Stays on Cold

The thermostat restricts the coolant from flowing through the radiator. If this gets stuck on wide open, the temperature might not reach optimal efficiency.

However, this will often make your temperature go up a bit from the minimum if you drive hard enough. If your temperature gauge is going up slowly, you might have a problem with the thermostat.

Reason 6: Presence of air or air bubble in the cooling system

The presence of air or air bubbles in the cooling system also causes the temperature gauge to remain cold.

If the Coolant temperature gauge is fluctuating, then an air bubble could be the reason. If the air is present in the AC system, you have to support a unique bleeding technique.

Reason 7: Damaged/defected engine control unit

The only reason behind damaging your engine control unit is using two pins for one temperature sensor by your car.

Rarely the problem could be your engine control unit. If ECM is receiving the temperature information first, you should use an OBD2 scanner to check the trouble codes.

If you do not have appropriate knowledge regarding the reading of trouble codes or measuring the temperature, you take the risk with your car and let a car electronics expert help you in this case. There is no need to replace the engine control unit until it is necessary as it is often costly and requires some coding.

Final Thoughts

Sometimes what happens is our car’s AC temperature gauge Shows the message of being cold, but in actuality, AC does not work. Then it’s time to get it repaired. There might be some reasons we mentioned above in this article. We have to change/repair some of its parts. If you are also facing the same problem, you can have some idea to get rid of it.

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