Checking Supply Voltage/Ground Terminal, Climate Control Module (CCM)

Checking the supply voltage/ground terminal

Checking the power supply and ground terminals

Power supply, climate control module (CCM)
The climate control module (CCM) is powered via a power input on the control module.
Power input terminal #1 (#25) is +15-supplied via a relay and fuse from the central electronic module (CEM). In the event of an open-circuit, the climate and infotainment functions cannot be activated.

Checking the power supply
Check the power supply cable from the central electronic module (CEM) to climate control module (CCM) terminal #1 (#25). Check for an open-circuit. Check for loose connections. Check for contact resistance. Check for oxidation. Check the fuse. The voltage must be approximately battery voltage.

Ground terminal, climate control module (CCM)
The climate control module (CCM) has a ground input. The ground input from the control module is power ground and is connected to the ground terminal in the car body. See the relevant wiring diagram for further information about the ground terminal.

Checking the ground terminal
Check the ground lead between climate control module (CCM) terminal #16 (#40) and the ground terminal. Check for an open-circuit. Check for loose connections. Check for contact resistance. Check for oxidation. With the ignition on, the drop in voltage between the ground connection and the ground terminal for the climate control module (CCM) must not be greater than 0.5 V.
Remedy as necessary.

Other information
- Connecting the breakout box Connecting the Breakout Box, Climate Control Module (CCM)
- Signal description Signal Description, Climate Control Module (CCM)
- See the relevant wiring diagram for information about circuit and ground terminals in the bodywork
- Checking wiring and terminals Checking Wiring and Terminals

Continue - DONE

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