Q: fan runs at high speed when car it turned on.

asked by on October 02, 2016

upon turning the automobile on, the Fan comes on at a high speed and never goes off until the car is turned off. Also the temperature gages in auto is incorrect.

My car has 300000 miles.
My car has an automatic transmission.

Hello there, you have a few different faults with your 2000 Mercedes. Your car’s fans have two speeds, low and high. The High speed setting should only be on during heavy load and high temperatures. The fans should shut off when driving and speed. The most common faults are the coolant temperature sensor, fan relay, failing fans, or a wiring harness fault. A qualified Technician such as one from YourMechanic will be able to diagnose your fan issues and make any repairs required.

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

What others are asking

The air conditioning, heater, and defroster are not working.

The symptoms you are experiencing can be caused by a few different things. If you are hearing a gurgling noise and your heater is not providing heat, then I would check the engine's coolant. If the coolant is low, it...

Exhaust leak unknown location near headers, p0170 code fuel trim malfunction bank 1 and white smoke when sitting in traffic.

Hi Kaden. Thanks for contacting us tonight. Usually when an exhaust leak occurs, it will cause the O2 sensors to relay faulty data to the ECU, which triggers the OBD-II code and will impact fuel trim, air mixture and several...

Car making noise like something is loose.

I would have a technician inspect the car for the noise. If something is loose it could be dangerous to drive.

Water pump

You do not have to remove or replace the timing belt in order to replace the water pump.

The transmission slips gears and the car has no kick down

If the transmission is slipping, then the vehicle will seem to not accelerate, or the vehicle will not move very fast. It seems that there could be an issue with the transmission that is causing the slippage. Check the kick-down...

I need a o2 sensor but i dont know how much it would cost or how many o2 sensors is on my car, i have a 2000 toyota camry v6

Hi Destiny. Thanks for contacting us today. There are a few different O2 sensors on your Toyota, but we need to know a bit more about your car, and the issues you're having to recommend the right inspection. If you...

shifting problems and the vehicle will not go backwards. Plus it will try to lunge forward in park.

Hi there. What could be the issue is the main valve to the transmission may have disconnected from the shifter lever on the side of the transmission. Raise up the vehicle and put it on four (4) jack stands. With...

Head Gasket leak

This is more of a judgment question as to how much you enjoy your car. A head gasket repair job can be costly and may generally run anywhere from $1,000-1,600 depending on the shop doing the repairs and what parts...

My car is overheating. The engine fan does not work unless the air conditioner is running.

Many vehicles have two separate fans. 1 fan is used for the engines radiator. The other thing is used only when the air conditioning is running. The fact that a fan kicks on when the air conditioning is running as...

Related articles

Symptoms of a Bad or Failing Cooling Fan Relay
Common signs include the engine running hot and cooling fans either not functioning or running all the time.
5 Comfortable Sports Cars Your Parents Won't Complain About Riding In
The most comfortable sports cars combine high performance with a smooth ride. Options include the Alpina B6, Audi S8 Plus, and Mercedes-AMG S65.
How to Replace an Ambient Temperature Sensor
The ambient temperature sensor monitors the car's temperature inside and out. This sensor allows the AC to maintain comfortable cabin temperatures.