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・Save up to 30%

Get a quote

What others are asking

Q: My air is blowing cold-hot-cold-hot-cold-hot...

It is possible that you have a leak in the AC system. There are pressure switches that will turn off the compressor if the pressure is too high or too low. The low refrigerant level could cause the AC compressor...

Q: HVAC is not working right

Hello. This is a programming problem. It is common on this vehicle. The HVAC module needs to be reprogrammed by the dealer to take care of this. Some of the time, the module will need to be replaced but most...

Q: module or unit?

Hi there. From the description you have provided, your vehicle Check Engine Light on with lots of warnings and exterior lighting acting weird, sounds like there may be a charging system related problem. I would recommend not driving your vehicle...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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.