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.

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

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General Description

Eight steering wheel control switches are used in order to control the audio and HVAC functions. The steering wheel controls are configured as a resistor network. Each switch has a unique resistance value. When the ignition switch is in the RUN or ACCESSORY position, ignition positive voltage is provided to the steering wheel controls from the IP fuse block radio fuse through the steering column fuse holder switch fuse (located at the base of the steering column) and the inflatable restraint steering wheel module coil on CKT 43 (YEL).

Pressing a steering wheel control switch causes voltage to pass through the resistor(s) to the radio on CKT 1011 (LT GRN). The radio processes the value received and commands the proper radio function. The radio sends a serial data message by the E and C serial data line on CKT 835 (DK GRN) to the HVAC system in order to control the proper function.