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

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With Base Standard and Base Clusters


The oil pressure switch, used on vehicles with the base instrument cluster, is a normally closed switch that opens with oil pressure. The switch opens with oil pressure after the engine is started. The switch closes when oil pressure drops below a specified limit. With the contact set closed, a ground is supplied for the oil pressure indicator lamp, allowing it to illuminate.