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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Electric Load Sensor Diode: Description and Operation

This signal is sent from each circuit of head & small (or clearance) lights, heater fan, radiator fan, stop light, rear window defogger and power steering pressure switch.

ECM uses it as one of the factors for controlling ISC solenoid valve operation.