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Home >> BMW >> 1990 >> 735i >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Trouble Code Diagnosis >> Malfunction Light Not On/No Start >> Main Relay
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Main Relay

Turn ignition switch to OFF position. Disconnect main relay (in control box at right or left shock tower). Perform voltage tests at relay connector as indicated in MAIN RELAY TESTS table. Correct any problems found. If voltages are as specified, replace main relay.

MAIN RELAY TESTS

Measure Between Correct Voltage If Voltage is Incorrect
No. 6 & Gnd. Battery (1) Battery
No. 8 & Gnd. Battery (1) Battery
No. 6 & No. 4 Battery (2) MCU No. 36
(1) Repair open in wire from indicated component.
(2) Repair open wire to indicated MCU terminal.
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