I believe it is aftermarket. We bought the motorhome second hand and was not running then. It had been towed by the previous owner and not used for 5-6 years. The alarm light in the cab does not flash at all if that helps. The immobiliser key does not seem to do anything, I have changed the battery in it but still does not do anything but the light on the immobiliser key now flashes.
We have tried what you told us to try but it still does not start. Do you have any further ideas.
Thank you we will try that. Definitely think it is something to do with being immobilised from being towed, We just do not know enough about the electric side of mechanics or immobilisers. Next step an auto electrician, if we can find one that can come out to the motorhome.
Sandy & Lance