Honda Multiplexing Board

1: Using the wiring diagram identify the plugs/pins and wire colours for the communication lines between the Nodes.
-Block B pin 1 (drivers) to block B pin 9 (passengers), pink wire
-Block A pin 15 (door) to block A pin 2 (drivers), brown wire

2: Using the wiring diagram identify the plugs/pins and wire colours for the Earths and voltage supply lines between the nodes.

Earths:  All wires are black
-from door Node, Block A pin 12 to G401 Block A pin 19 to G581=LHD, G581=RHD
-From drivers node, B11 to G501, A14 to G401, B22 to G501, A8 ro G401
Inputs:
-To door node, pink wire A1 to drivers-white/black wire to A1
-pink wire A12, fuse relay box socket (no wire) A24 to passengers node fuse box relay socket A24, yellow wire A22.

Ask your instructor to create a fault in the unit, describe how this fault is affecting the normal operation of this system.
-The passenger, back left, back right window acuators are not working and the central locking actuator isnt working.
By using the wiring diagram i diagnosed the fault and came to a conclusion that the communication wire is split.

After reading the manual put the system in to test modde 1 and record any faults, how many times the node beeps.
we got 1 short beep which means the drivers unit is not able to receive signals from the door unit.

to test the fault you have to do a voltage drop test not a resistance check because you cannot unplug the wires and cannot injuce a current because it can damage components.
when i did the voltage drop test i got a value of 0.2V DC across the brown communication wire which means there is a split in the wire because the wire is bi-directional so both ends are trying to send signals.

The door unit has no inputs to the drivers unit because i discovered in question 4 that the brown communication line was split or open circuited which is stoping the door node from sending signals to the driverside node.

using the wiring diagram from the back of the manual describe what tests you would carry out now and what results you would expect. Note wire colours pin/block numbers.
Do a voltage drop test between A15 and A2 and it should be 0V if it was good but in our case there was a volt drop of 0.2V because at pin A15 it was 8.7V and at A15 it was 8.5V. This volt drop indicates there is a break in between A15 and A2, another test you could do is a continuity test but you cant do this while the drivers node is plugged in so what you have to do is unplug the whole drivers node and unplug the plug at the door node.