Skip the auto shop - Our mechanics make house calls

Q: the high speed of coolant fan doesn't turn on when the engine overheats

asked by on

its the opel astra G CD 2004 the car is a Brazilian made for Chevrolet (in Brazil called Chevrolet astra) but came to Egypt under the Opel name from the GM factory in Brazil with z16xe engine and an auto transmission with HSFI 2.1 ecu, it originally has an HSFI 2.3 ecu that came with the car from the factory, but it showed malfunctions and had to be replaced and HSFI 2.3 wasn't available later the ecu dropped signal to the fuel pump relay and the car wasnt able to start, the local mechanic repaired it by getting a separate 12v signal only when the ignition is on through a diode from a near by relay and the car was pumped back to life (this isnt the main problem but i wanted to denote a faulty ecu) now the ecu dropped signal of the high speed radiator fan so it would turn on but only on the low speed thus on daily use there is no overheating unless I open the A/C in traffic jams while on the highway it cools back can I check for wiring error at the relay box or change wiring or what?

My car has 7427871 miles.
My car has an automatic transmission.

A: Hi there. The high speed cooling fan is usu...

Hi there. The high speed cooling fan is usually controlled by a spectate thermal switch, so it’s possible that this thermal switch has failed. However, you should try as hard you can to obtain the correct ECU for this car, as that can only improve the situation. If you need help with this have a local expert diagnose the AC system to assist with proper repair.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Radiator cooling fan is not functioning on low power

The resistance reading you tested sounds like it's in range. Most likely the coolant temperature sensor/switch, which controls the fan (on the radiator side tank), has failed and isn't connecting power to the fan when the temperature reaches the design...

Q: How could I fix my strategy code FBJR2G3 on my 2005 mustang GT.

There should be a 1-800 number to call the SCT tuner people with questions. Not all tuners will work with every model of engine and computer strategy. The Engine Control Unit (ECU) program from the factory is saved in...

Q: Hesitation while accelerating and engine overheating on a '94 Toyota Corolla

The main problems this vehicle has for that problem are the spark plugs, distributor cap, and the wire set. On these older cars they are a one piece unit and just go bad. You will need to replace it. If...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.