A Full Frontal Node

This is a collection of devices previously described that are directly connected to the J-Front (Left) Node at the front-right of the vehicle; one of the busiest nodes in the vehicle as it connects to a very wide range of devices.

This is a big muddy map sketching out how things are directly connected. Click on the image to open it in a new window.
Starting from the left, it manages alternator excitation and monitoring, engine start; radiator fan operation; oil pressure and temperature sensors and switches; coolant temperature, coolant level and ambient air temperature sensors for the instrument panel; all the lights on the front-left of the vehicle, monitors the reverse light switch, operates the horns, drives the windshield washer pump and operates the airconditioning compressor clutch according to pressure and temperature switches and command received over the LINbus.

In tabular form:

J-Front (Left)
Track Colour(s) Size mm² Device Device Port Remarks
7 ro 4.0 B 50 Starter Solenoid
7 ge 6.0 BDB SA1 Power supply for J-Front
8 ro/ws 0.5 B 15a Starter Solenoid closure feedback
8 bl 0.5 C/C1 D+ Alternator excitation and monitoring
14 gn/sw 1.0 J293 3 Radiator Fan PWM
15 sw 1.0 J293 4 Radiator Fan KL_15
15 ro/li 1.0 F18 3 Radiator Thermoswitch common
16 ro/sw 1.0 F18 1 Radiator Thermoswitch 105°
17 ro/ws 1.0 F18 2 Radiator Thermoswitch 95°
20 ws/ge 0.5 J-InstAux GALA Road speed signal ex speedometer cable
63 gn/bl 0.5 J-Central? RPM Engine speed (ignition pulses)
63 or/ws 0.5 F87 Radiator Fan Post-Run 110°
71 li/ws 0.5 LIN LIN LIN-bus
71 br/ro 0.5 Common
72 bl/ro 0.5 G32 2 Coolant level
73 ge/ro 0.5 G2 2 Coolant Temp. Gauge sensor
74 bl/sw 0.5 F22 Oil Pressure 0.3 Bar
75 ge 0.5 F18 Oil Pressure 1.8 Bar
114 gn/sw 0.5 G8 Oil Temperature sensor
117 ws/ro 0.5 G17 2 Air temperature sensor
118 br/ge 0.5 G17 1 Air temperature sensor
155 br 2.5 Main Chassis at front left common (119)
157 ws 1.0 L13 1 Driving Light Left
158 ws/sw 1.0 L1 56a Headlight Low beam Left
159 ge/sw 1.0 L1 56b Headlight High beam Left
160 gr/sw 0.5 M1 1/58 Park light left
183 sw/ws 1.0 M5 BLL Indicator Front Left
1.0 M? Side Repeater Left (not shown)
191 ws/ge 1.0 L22 1 Fog Light Front Left
207 sw/bl 1.0 F4 2 Reverse Light switch
208 sw/ro 1.0 F4 1/58 Reverse Light switch
224 sw/ge 1.0 H1 C13 Dual tone horns
255 gn/ro 1.0 V59 1 Washer pump (reversible)
256 br/ge 1.0 V59 2 Washer pump (reversible)
[16] ro/gn 1.0 Switch A/C Low Pressure 2 Bar
[17] gn 1.0 Switch A/C Thermoswitch on engine 119°
[18] br/ws 1.0 common
[18] ro/sw 1.0 Compressor A/C Compressor Clutch
[19] ro/ws 1.0 Switch A/C High Pressure

All quite preliminary with simplifications and complications likely as well as cable colour and cross-sectional area changes possible during the design evolution of the node. More devices may be added. Some may be delegated to connection to other nodes.

There are 3 “bus” connections; LINbus obviously; engine RPM signal which is a buffered repeat of the ignition control pulses by J-Central; and road speed, buffered out of the GALA output signal from the stock instrument cluster by J-InstAux. Engine speed is necessary for the management of the engine start flick-to start process and road speed is useful for reducing radiator fan speed once the vehicle is moving quickly enough.

If you’re counting; that makes it about 40 connections into or out of the node to the surrounding devices. A few very heavy ones; mainly for power, the starter solenoid (which’d consume the most power via the node) and chassis ground. But most others are of small cross-section because they only monitor switch state or carry a small current to operate a sensor.

The headlights of course carry significant current; but nothing that a copper cross-section of 1mm² can’t handle; even when heated by the nearby radiator.


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