TECH TIP
MERCEDES KEY WILL NOT TURN IN IGNITION
Aug. 06 2019
Aug. 06 2019

Vehicle: 2004 Mercedes Benz S 430 (220.170), V8-4.3L (113.941), Automatic Transmission

Mileage: 199,776

Problem: The vehicle was towed in because the key would not turn on the Electronic Ignition Switch (EIS).

Mercedes Wire Diagram


Details: The technician attempted to communicate with the EIS, it was not possible. At that point, he called Tech-Assist.

The Tech-Assist consultant studied the wiring diagram and found a possible problem. In the Power Distribution diagram, fuse #78 in the Cockpit Fuse Box powers the EIS itself (see the wiring diagram below).

The technician inspected fuse #78 and found that it was cracked.

Confirmed Repair: He replaced the fuse and that repaired the problem. st

The ALLDATA Tech-Assist team fields cases like this every day. See how Tech-Assist can help your shop save time and money with on-call diagnostic support from ASE-certified Master Technicians. More Tech Tips 

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