No passenger low beam - fuse & bulb fine

[Antoin]

Checked the CEM multiplugs.
The blue one has no corrosion at all, the bigger green plug has very minimal corrosion deposits on one pin. If I wasn't looking for it I wouldn't even give it a second glance.
The actual area appears to be bone dry so I don't believe moisture ingress is any reason for failure.

I plugged in VIDA and got the following error code;

372: CEM-8A20 Low Beam Left. Signal too low
Check the power cable for short circuit to ground.

It is asking me to check wire between B7 (CEM plug) and A2 (Headlight plug)

Am I right in thinking that a short circuit is not a completely broken wire and that it has likely chafed off the insulation somehwere and is contacting the body of the car?

[Simmy]

did you check the shunts they look like a large 5 blade fuse if your car has them. try swopping them to see if the problem moves sides look for any chafed wires in or near the h light . look at the wireing diagrams on vida to see which wires are used.

[Antoin]

Originally Posted by Simmy

did you check the shunts they look like a large 5 blade fuse if your car has them. try swopping them to see if the problem moves sides look for any chafed wires in or near the h light . look at the wireing diagrams on vida to see which wires are used.

Thanks Simmy.

Are the shunts on the CEM board?
My CEM board appears to be sealed from looking in the footwell, no relays or AN Other visible.

[Antoin]

Just to close this out I had another stab at this last night and now I have a working dipped passenger beam again.

To do this I removed the earths near passenger strut, cleaned them up and refitted.
Changed both bulbs for brand new, passenger and drivers. Both the original bulbs still worked but perhaps the imbalance in them was making the CEM throw a wobbly!



I cant tell which fixed the issue.