Hi all, I have a strange problem with my 2008 L322 TDV8. The LH rear indicator is not working properly. The car does have aftermarket LED rear clusters (which have never given scanbus errors), which have been working fine for the past couple of years, since being fitted. Currently, I am getting the fast blinking on the LH side and the rear indicator is flashing dimly (and only appears to be getting 1-2V. With the hazards on, the rear LH indicator doesn't flash at all. There is a bypass relay hooked into that circuit for the tow electrics, but I have disconnected that in case it was dragging the voltage down. I have also ran a clean earth to the indicator circuit in the light assembly, so have also discounted that. I am now guessing that it could be the LCM itself which is the issue. Assuming I can get to the LCM (which I believe in behind the panel adjacent to the bonnet release?) can I simply try swapping the rear circuit with either the front or side circuit to prove it's the LCM? Any other tests I can do?

Getting this fixed is quite urgent as I'm overdue my annual test.