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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Heater-A/C Control

With the ignition switch in the ON position, voltage is supplied through the HVAC fuse and circuit 41 (BRN) to the heater-A/C control assembly. The voltage from circuit 1199 (DK BLU) is varied from B+ to approximately 1.5 V by the temperature control potentiometer. The heater-A/C control receives ground from G200 through circuit 1450 (BLK).