Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

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Alternator No-Load Test

NOTE: Prior to testing, turn headlamps ON for 10-15 seconds to remove battery surface charge. Wait until voltage stabilizes before performing test.

1. Connect Rotunda 88 Digital Multimeter 105-00053, or equivalent.
2. Connect Rotunda 73 Digital Multimeter 105-00051, or equivalent, across battery terminals and record base voltage.
3. Start engine and run at 1500 RPM with no electrical load.
4. Voltage should be 14.1-14.7 volts.
5. If voltage increases, but increase is less than 2.5 volts, perform Load Test. Load Test
6. If voltage does not increase, or increases more than 2.5 volts, perform Output Test. Output Test