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Alb (Mk2 MP350)
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Discussion Starter · #1 ·
This is the Ford procedure for testing the Alternator.

Thought it worth posting because the question is asked on a regular basis and you can do this anywhere using the dashboard voltage display.

Generator On-Vehicle Tests - No-Load Test

1. Turn off all electrical loads and the ignition switch.
2. Switch the multimeter to the voltage function.
3. Connect the leads of the multimeter across the battery terminals.
4. Read the voltage (base voltage).
5. Start the engine.
6. Run the engine at 1500 rpm with no electrical load.
7. Read the voltage. The voltage should be in the range of 14.1 volts to 15.1 volts. If the voltage increase is less than 2.5 volts above the base voltage, carry out the Load Test.

Generator On-Vehicle Tests - Load Test

1. With the engine running, turn on the air conditioning (if equipped), turn the blower motor to high speed and the headlamps to high beam.
2. Increase the engine speed to 2000 rpm. The voltage should increase a minimum of 0.5 volts above the base voltage. If the voltage increases as specified, the charging system is charging correctly.
 

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RS mk2 MR375
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:unsure: You cant use hte dashboard voltage display as you cant get the no load baseline figure... Step 1 says turn off hte ignition switch, so no dashboard power.... You still need a multimeter.
 

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Alb (Mk2 MP350)
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Discussion Starter · #4 ·
Good point Mark but I think the process is still quite valid with ignition on (but nothing else), as I found it made a minuscule difference to the displayed voltage.

For the vast majority of failed alternators, the no load engine running test will reveal the problem anyway :)
 

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Testing an Alternator Manually
Now that we’ve gone over some of the signs of a bad alternator, let’s talk about how to actually test one without a multimeter. While a multimeter is the most accurate way to test an alternator, there is a way to test it manually.
 
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