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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Coolant Switch Test


1. With ignition Off, disconnect electrical connector from coolant switch.
2. Connect an ohmmeter to switch. Connect one probe to a ground and other probe to coolant switch terminal.
3. On a cold engine, there should be continuity. If not, replace switch.
4. On a hot engine (at normal operating temperature), there should be no continuity. If there is continuity, replace switch.