E2012 Main beam
- Make
- Alfa Romeo
- Model
- 147 Factory Service Manual
- Year
- 2000–2002
- Section
- Exterior lighting › E2012 Main beam
E2012 Main beam
Description
The vehicle has two main beam headlamps in the light cluster.
The main beam headlamps are switched on by the steering column switch unit:
- when the dipped beam headlamps are on, by pressing the lever towards the dashboard (stable mode)
- in 'flash' mode, by pulling the lever towards the steering wheel (unstable mode)
The relay for switching on the dipped headlamps is managed by the Body Computer: the energizing of the relay is activated by the go ahead signals with the ignition key in the ON position (INT) and by the specific signal from the steering column switch unit.
The activation and/or deactivation information is sent via the CAN: in this way the main beam warning light in the instrument panel is also switched on.
The Body Computer also manages the 'dipped headlamps maintenance' function: when the main beam headlamps are on, the Body Computer keeps the dipped headlamps on Wiring diagram E2011 DIPPED HEADLAMPS .
Description of operation
The main beam headlamps activation signal is sent to pin 33 of connector B of the Body Computer M1 from the steering column switch unit H5.
The 'key in ON position' signal (INT) from the switch H1 reaches the underdashboard control unit B2 at pin 11 of connector H and from there moves on to the Body Computer M1 (pin 9 of connector F).
The Body Computer M1 controls the supply to the main beam headlamps by sending an earth signal to the engine compartment control unit B1- from pin 9 of connector A of M1 - which energizes the relay T2: this supplies the dipped headlamps F10 (left) and F11 (right). Each circuit is protected by a control unit B1 fuse: F15 for the left headlamp and F14 for the right one.
The Body Computer M1 is connected, via the CAN line, to the instrument panel E50 to manage the main beam headlamps warning light.
Wiring diagram
Components
| Code | Component | See |
|---|---|---|
| B01 | Engine compartment junction unit | description 5505A |
| B02 | Junction unit under dashboard | description 5505A |
| B99 | Maxifuse box on battery | description 5530B |
| C10 | Front left earth | |
| C11 | Right front earth | |
| C15 | Facia earth, driver's side | |
| E50 | Instrument panel | description 5560B |
| F10 | Left headlamp | description 5540B |
| F11 | Right headlamp | description 5540B |
| H01 | Ignition switch | description 5520A |
| H05 | Stalk unit | description 5550A |
| M01 | Body computer | description 5505A |
Component location
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