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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.
| Car | Service | Estimate | Shop/Dealer Price |
|---|---|---|---|
| 1987 Mercedes-Benz 420SELV8-4.2L | Service typeElectronic Control Relay Replacement | Estimate$207.35 | Shop/Dealer Price$247.94 - $330.34 |
| 1990 Mercedes-Benz 420SELV8-4.2L | Service typeElectronic Control Relay Replacement | Estimate$187.35 | Shop/Dealer Price$227.97 - $310.39 |
| 1988 Mercedes-Benz 420SELV8-4.2L | Service typeElectronic Control Relay Replacement | Estimate$187.35 | Shop/Dealer Price$227.97 - $310.39 |
| 1986 Mercedes-Benz 420SELV8-4.2L | Service typeElectronic Control Relay Replacement | Estimate$187.35 | Shop/Dealer Price$227.93 - $310.32 |
| 1989 Mercedes-Benz 420SELV8-4.2L | Service typeElectronic Control Relay Replacement | Estimate$187.35 | Shop/Dealer Price$228.00 - $310.44 |
| 1991 Mercedes-Benz 420SELV8-4.2L | Service typeElectronic Control Relay Replacement | Estimate$187.35 | Shop/Dealer Price$227.97 - $310.39 |
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.
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.
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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