Mercedes-Benz E420 Cooling Fan Relay Replacement at your home or office.

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Cooling Fan Relay Replacement Service

How much does a Cooling Fan Relay Replacement cost?

On average, the cost for a Mercedes-Benz E420 Cooling Fan Relay Replacement is $161 with $66 for parts and $95 for labor. Prices may vary depending on your location.

CarServiceEstimateShop/Dealer Price
1995 Mercedes-Benz E420V8-4.2LService typeCooling Fan Relay ReplacementEstimate$246.95Shop/Dealer Price$297.44 - $409.54
1997 Mercedes-Benz E420V8-4.2LService typeCooling Fan Relay ReplacementEstimate$226.95Shop/Dealer Price$277.47 - $389.59
1994 Mercedes-Benz E420V8-4.2LService typeCooling Fan Relay ReplacementEstimate$226.95Shop/Dealer Price$277.47 - $389.59
Show example Mercedes-Benz E420 Cooling Fan Relay Replacement prices

What is the Cooling Fan Relay all about?

Modern vehicles employ electric cooling fans to draw air into the engine compartment, through the radiator, and into the air conditioning condenser. This action removes heat from the coolant in the radiator and pulls heat from the refrigerant in the air conditioning condenser. The electric cooling fan is an electric motor with fan blades attached to it. It turns on when the powertrain control module receives a signal that the temperature of the engine or air conditioning warrants the extra flow of air.

The powertrain control module then sends a signal for the cooling fan relay to supply power to the cooling fan. The fan motor relay performs the action of a switch, sending 12-volt power to the cooling fan and initiating its operation. Once the engine temperature drops below the threshold programmed into the powertrain control module, the cooling fan turns off. In some makes and models, the cooling fan can continue running after the engine has been shut off, or it can turn on while the ignition is off. If the cooling fan relay is faulty, the cooling fan can continue to run unnecessarily, even when the ignition is off and the engine is cold. Conversely, the cooling fan may not run at all causing the engine to overheat. Since the cooling fan plays a factor in air conditioning performance, your air conditioning may not blow cold air.

Keep in mind:

  • The cooling fan can run even with the ignition off. Use caution when working in and around the cooling fan to prevent personal injury.
  • Some vehicles are equipped with two cooling fans, with separate cooling fan relays controlling each one.

How it's done:

  • The Cooling Fan Relay is verified that it needs to be replaced. The main access relay panel is open to access the cooling fan relay.

  • The defective Cooling Fan Relay is removed from the relay box by pulling straight up and out of the connection.

  • The connection is checked for any damage or overheating. The new Cooling Fan Relay is installed by lining up the pins and pressing it into the connection.

  • The Cooling Fan Relay is tested for operation by running the engine or turning on the A/C.

  • The vehicle is tested for proper operation of the Cooling Fan during a road test.

Our recommendation:

The cooling fan relay is meant to last indefinitely, but as with all electrical components, it can fail prematurely. There are no preventative measures you can take against its failure. If your engine temperature rises into the red zone, or if the cooling fan won’t quit operating, have one of our expert technicians diagnose the problem and replace the cooling fan relay if required.

What common symptoms indicate you may need to replace the Cooling Fan Relay?

  • Engine temperature runs higher than normal or overheats
  • Air-conditioning does not function
  • Cooling fan continues to run indefinitely

How important is this service?

The electric cooling fan plays an important role to control engine temperature. In a situation where the cooling fan will not turn on, overheating and engine damage can occur. If the cooling fan runs continuously, the fan motor can burn out or electrical drain can deplete your battery. If the cooling fan relay is faulty, have it replaced as soon as possible to prevent additional, expensive repairs.

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Meet some of our expert Mercedes-Benz mechanics

Real customer reviews from Mercedes-Benz owners like you.

Excellent Rating

(24)

Rating Summary
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Bill

21 years of experience
23 reviews
Bill
21 years of experience
Mercedes-Benz E420 V8-4.2L - Oil Change - Aliso Viejo, California
Knowledgeable, honest, and professional!

James

23 years of experience
99 reviews
James
23 years of experience
Mercedes-Benz E420 V8-4.2L - Steering Rack/Gearbox - Marietta, Georgia
Excellent service. Very knowledgeable and meticulous, ensuring that the work is flawless before he leaves. I highly recommend James.

Jesus

16 years of experience
68 reviews
Jesus
16 years of experience
Mercedes-Benz E420 V8-4.2L - Pre-purchase Car Inspection - Long Beach, California
I requested a pre purchase inspection for a car about 200 miles away from where I live. Jesus was on time, responsive, and very pleasant to work with. He kept me abreast of his inspection and provided me his professional feedback on the status of the vehicle. He followed up with a comprehensive and easy to understand report of his findings. Awsome service and awesome professional mechanic. Thank you.

Andrew

11 years of experience
354 reviews
Andrew
11 years of experience
Mercedes-Benz E420 V8-4.2L - Engine is running louder than normal Inspection - Glen Burnie, Maryland
Andrew was on time and knowledgeable. He was honest to determine no work was necessary. He took the time to research another mechanic issue and gave a quote.

Excellent Rating

(24)

Rating Summary
18
2
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3
18
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Number of Mercedes-Benz E420 services completed
264+
services done by our mechanics
TOTAL NUMBER OF EXPERT Mercedes-Benz MECHANICS
1100+
experts on our platform

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