9-3 FWD (9440) L4-2.0L Turbo (B207R) (2009)
Transistor Drivers
Transistor Drivers activate the components that perform the task for the CPU by, for example, grounding a relay coil or an interior lighting bulb.
The power amplifier transistors are power grounded, often through an extra thick pin in the connector. The lead, often 1-2.5 mm2 then goes to the body
and is grounded separately from the signal ground, which feeds other internal components of the control module.
If there are great loads, such as from the radiator fan, ventilation fan, fuel pump or glow plug, additional power amplifiers or relays may be used.