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)

Or, hide this message: temporarily or permanently

Test P: The Steering Wheel Control Switch Is Inoperative/Does Not Operate Correctly

PINPOINT TEST P: THE STEERING WHEEL CONTROL SWITCH IS INOPERATIVE/DOES NOT OPERATE CORRECTLY

Normal Operation
Under normal operation, the electronic automatic temperature control (EATC) module senses the resistance (depending on what button is pressed) from the steering wheel control switch through circuit 1070 (BN/LB). Ground for the steering wheel control switch is provided through circuit 57 (BK).

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Steering wheel control switch
- EATC module


P1-P3:






P3-P5: