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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A/C Signal: Testing and Inspection

1. Position the vehicle on a chassis roller and start the engine.
2. Shift the selector lever into other than P and N.
3. Turn the A/C switch and the fan switch on.
4. Fully open the throttle valve. Then, 3 - 6 seconds after, inspect if the operation sound of the A/C compressor electromagnetic clutch is heard.
- If the operation sound is not heard, proceed to next stop.
5. Turn the ignition switch on.
6. Turn the A/C relay from OFF to ON by connecting a jumper wire between LG/Y terminal of A/C relay connector and ground, and inspect for the operation sound of the relay.
- If the operation sound is heard, inspect the PCM terminal voltage.
- Load/no load distinction signal
- Closed throttle position signal
- If the operation sound is not heard, inspect the following.
- A/C relay
- Open circuit in wiring harnesses and connector (PCM control relay - A/C relay - PCM)