Trailer Module
Trailer Module
The trailer module is fitted to all vehicles and is located in the RH side of the luggage compartment behind the removable trim panel adjacent to the rear fusebox. The module is required to separate the load circuits of the trailer from the load circuits of the towing vehicle. This allows separate monitoring of the vehicle lamps and the trailer circuits.
The trailer module comprises a double transistor for reverse lamp and rear fog lamp operation and overload proof MOSFET circuit breakers for the following lamps:
- Left direction indicator
- Right direction indicator
- Brake lamps
- Left tail lamp
- Right tail lamp
- Permanent trailer battery supply circuits.
The above lamps are connected to the trailer module via direct connections to the applicable lamps. The rear fog lamps and reverse lamps are not directly connected to the lamps Units because these lamps must be disabled when the trailer socket is connected.
The LCM communicates with the trailer module via a bi-directional, dedicated serial link. The rear tog lamps and reverse lamp are controlled on this link. The trailer module also uses this Ink to transmit error messages for the trailer lamps to the LCM.
The trailer module has two modes of operation; sleep mode and normal mode. Sleep mode is initiated by the LCM after a predetermined time. In this mode the trailer module processor clock speed is reduced to a minimum and all loads are switched off to keep current consumption to a minimum. The module operates in normal mode on receipt of an applicable message from the LCM. The required loads and the current supply for bulb failure detection are activated.
The LCM communicates with the trailer module every 2 seconds with a normal mode telegram. If the trailer module no longer responds the data link to the module is switched low for 1 second after ten unsuccessful attempts to establish the communication. When the LCM switches the data link low the trailer module is 'reset'. If communication is not established after thirty attempts in succession, the LCM assumes the module is defective and records an applicable error message in the error memory.
If a replacement trailer module is fitted the LCM instantly recognises it via the data link. Connection of TestBook/T4 is not required to establish communications between the LCM and the trailer module.
Instrument Panel and Switch Illumination Dimming
The LCM controls the instrument pack backlighting illumination and also illumination of all switches.
The LCM supplies a power output to all switch illumination bulbs at a voltage determined by the position of the manual dimmer rheostat. The switch illumination is activated when the light control switch is in the side lamp or headlamp position.
Diagnostics
The diagnostic socket allows for the transfer of information between the LCM, the automatic headlamp levelling ECU and TestBook/T4. The diagnostic socket is located in the fascia, in the driver's stowage tray. The socket is secured in the fascia and protected by a hinged cover.
The LCM has diagnostic capabilities and store fault codes relating to the lighting systems. The xenon control modules cannot be interrogated via the LCM but the LCM incorporates xenon specific diagnosis up to the control modules.
The xenon control modules, located on the rear of the headlamp assemblies, can be interrogated using TestBook/T4 for faults relating to the operation of the xenon lamps. The control modules are connected on a DS2 link to the diagnostic socket.