Mercedes-Benz 420SEL Electronic Control Relay Replacement at your home or office.

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Electronic Control Relay Replacement Service

How much does a Electronic Control Relay Replacement cost?

On average, the cost for a Mercedes-Benz 420SEL Electronic Control Relay Replacement is $141 with $46 for parts and $95 for labor. Prices may vary depending on your location.

CarServiceEstimateShop/Dealer Price
1987 Mercedes-Benz 420SELV8-4.2LService typeElectronic Control Relay ReplacementEstimate$207.35Shop/Dealer Price$247.94 - $330.34
1990 Mercedes-Benz 420SELV8-4.2LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$227.97 - $310.39
1988 Mercedes-Benz 420SELV8-4.2LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$227.97 - $310.39
1986 Mercedes-Benz 420SELV8-4.2LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$227.93 - $310.32
1989 Mercedes-Benz 420SELV8-4.2LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$228.00 - $310.44
1991 Mercedes-Benz 420SELV8-4.2LService typeElectronic Control Relay ReplacementEstimate$187.35Shop/Dealer Price$227.97 - $310.39
Show example Mercedes-Benz 420SEL Electronic Control Relay Replacement prices

What is the Electronic Control Relay all about?

A wide range of electronic systems must work properly in order for the vehicle to operate. That means there is a need for several different controllers to ensure proper operation. One of the most important is the electronic control relay. You might be more familiar with the term “main relay” because of its role in vehicle performance.

The electronic control relay operates the fuel pump and sends power to the engine’s injectors. Without the main relay, fuel will not flow from the tank to the engine, and your injectors will not atomize gasoline into the combustion chamber. In short, your car wouldn’t run. Electronic control relays are subject to failure from a number of different problems, including outright failure, heat damage, cracked solder and more.

Keep in mind:

  • The electronic control relay may not operate, or may operate intermittently depending on the source of the trouble.
  • A number of other problems can masquerade as a main relay failure, so it’s vital that you have one of our expert mechanics diagnose the issue.

How it's done:

  • The electronic control relay is located and accessed then verified it needs replaced
  • The defective relay is removed from the vehicle
  • The new electronic relay is installed
  • The components that the electronic relay operates are checked for proper operation
  • The vehicle is road tested for proper operation

Our recommendation:

Traditional turnkey ignition the relay will click three times during the starting process. If you listen closely, you should hear a single click when you turn the ignition to “on”. You should hear another when the Check Engine light turns off. Finally, there should be a third click when you turn the key to the “start” position. If you do not hear a click at any of these three points, there may be a problem with the electronic control relay. Have one of our expert mechanics diagnose and replace the relay if required.

What common symptoms indicate you may need to replace the Electronic Control Relay?

  • Engine doesn’t start, especially in cold weather
  • Engine may not start a few minutes after turning it off
  • No sound from the fuel pump when the ignition key is turned to “On”

How important is this service?

Given the fact that the electronic control relay powers the fuel pump and your fuel injectors, it is essential to replace a faulty one. However, many other problems can present similar symptoms, so it’s very important to have the issue diagnosed by one of our expert mechanics.

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Meet some of our expert Mercedes-Benz mechanics

Real customer reviews from Mercedes-Benz owners like you.

Excellent Rating

(18)

Rating Summary
17
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1
0
17
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Sayeed

17 years of experience
82 reviews
Sayeed
17 years of experience
Mercedes-Benz 420SEL V8-4.2L - Power Steering Fluid Service - Copiague, New York
Excellent

Luther

16 years of experience
57 reviews
Luther
16 years of experience
Mercedes-Benz 420SEL V8-4.2L - Inspection / Diagnostics - Atlanta, Georgia

Patrick

33 years of experience
1441 reviews
Patrick
33 years of experience
Mercedes-Benz 420SEL V8-4.2L - Car is not starting - Pflugerville, Texas
Very good.

Tien

23 years of experience
903 reviews
Tien
23 years of experience
Mercedes-Benz 420SEL V8-4.2L - Power Window Switch Replacement (Passenger Side Front, Passenger Side Rear) - Oakland, California
Tiens was very nice to work with. He fixed 2 things and ordered parts for other items.

Excellent Rating

(18)

Rating Summary
17
0
0
1
0
17
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1
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Number of Mercedes-Benz 420SEL services completed
198+
services done by our mechanics
TOTAL NUMBER OF EXPERT Mercedes-Benz MECHANICS
1100+
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