ROTOR-EXCITER 7E6557 - Caterpillar

627E, 637E and 657E Scrapers
Problem: Engine will not crank.
Make sure the Tractor transmission is in the neutral position. Perform the following tests with the Tractor key switch in the "ON" position.
Battery voltage and high amperage are present. Injury to personnel is possible.
1. Check the circuit breaker. Place the key switch in the "ON" position. Check the scraper instrument panel lamp. The lamp gets its power from the same circuit breaker as the key switch and Neutral Start Control. If the lamp works, there is current flow through the breaker. If the lamp does not work, trace and repair the circuit.2. Check the voltage available. Set the meter selector switch to the 200DCV range. Connect the leads to the start relay coil. Check the voltage across the start relay coil when cranking is attempted. If 20V or more is present, the problem is NOT in the Neutral Start Control or related electrical system. Use the 6V2150 Starting and Charging Analyzer to identify the problem area.3. Check inputs to the Neutral Start Control.
Five Socket, Four Pin Sure-Seal Connector (Harness End)
(1) socket one. (2) Socket two. (3) Pin three. (4) Pin four. (5) Pin five. (6) Pin six. (7) Socket seven. (8) Socket eight. (9) Socket nine.Disconnect the five socket, four pin Sure-Seal connector from the control. Perform the following tests on the wiring harness connector.Set the meter selector switch to the 200DCV scale. Connect