Ce-niehoff-co N1128 Troubleshooting Guides Uživatelský manuál stáhnout pdf (Strana 6)

Page 6

TG0027A

Section 4: Advanced Troubleshooting

(CONT’D)

Shut off engine. With key off, engine off: Test for battery voltage at alternator 28 V B+

terminal. Does battery voltage exist?

Ye s

Check and repair wiring and battery cables as necessary.

Continue test.

Chart 1 – 28 V LED Steady AMBER – No 28V Alternator Output – Test Charging Circuit

With DMM, check resistance across field coil. Connect red lead of DMM to socket A in alternator-to-regulator

harness plug. Connect black lead to B+ terminal on alternator. Does meter show 1.8 to 2.2 ohms?

Ye s

Yes

Test phase signal into regulator (AC). Set meter to diode tester:

Connect red lead of DMM to socket C of regulator harness and black

lead to socket B. Meter should show voltage drop value.

Then reverse meter lead connections. Meter should show OL (blocking).

Yes

Regulator responded to overvoltage condition. Go to Chart 4

on page 8 to troubleshoot OVCO.

Figure 3 – Alternator-to-Regulator

4-Socket Harness Plug

SOCKET CONNECTIONS

AF–

B Phase Signal AC

CB–

D 28 V B+

With key on, engine running: Test for battery voltage between IGN terminal on regulator and alternator

B– terminal. Does 28 V battery voltage exist?

Ye s

With key off, engine off: Remove alternator-to-regulator 4-pin harness from regulator. Test for battery

voltage across sockets D and C in harness plug. Does 28 V battery voltage exist?

Alternator is defective.

Regulator is defective.

Ye s

Connect jumper wire from socket A in regulator harness plug to B– terminal on alternator.

Spark will occur. Touch steel tool to shaft to detect significant magnetism. Is shaft magnetized?

Repair vehicle ignition circuit wiring as necessary. Continue test.

Yes

Start engine. Wait 20 seconds. Is 28 V LED steady GREEN on regulator?

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Ce-niehoff-co N1128 Troubleshooting Guides Uživatelský manuál Strana 6