MBE 900 DDEC VI Troubleshooting – Section 5.5 Defective Magnetic Switch

Section 5.5
Defective Magnetic Switch

To determine if a defective magnetic switch is causing starting difficulty:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

1. Start the engine.
2. Clamp a heavy gauge battery jumper cable between the two large studs of the magnetic switch. See Figure "Basic Cranking Circuit" .
   

   1. Ground Return‪	4. Starter‪
   2. Starter Switch‪	A. Stud‪
   3.Magnetic Switch‪	B. Starter Stud‪

   Figure 1. Basic Cranking Circuit

   1. If the engine cranked with the jumper cable in place, the magnetic switch must be replaced; refer to "5.5.1 Magnetic Switch Replacement" .
   2. If the engine did not crank with the jumper cable in place, check the starter; refer to "5.6 Defective Starter" .

Section 5.5.1
Magnetic Switch Replacement

Perform the following steps for magnetic switch replacement:‪

1. Replace the magnetic switch; refer to OEM guidelines.
2. Verify magnetic switch replacement; refer to "5.5.1.1 Test Engine with Replaced Magnetic Switch" .

Section 5.5.1.1
Test Engine with Replaced Magnetic Switch

To determine if the magnetic switch replacement resolved the starting difficulty, perform the following steps:‪

PERSONAL INJURY ‪
To avoid injury before starting and running the engine, ensure the vehicle is parked on a level surface, parking brake is set, and the wheels are blocked.‪

1. Attempt to start and run the engine, if the engine starts and runs, no further troubleshooting is required. Shut down the engine.
2. If the engine fails to start and run, check the starter; refer to "5.6 Defective Starter" .