L333spt

So my landrover d2 v8 had a issue key fob not responding unlock door with key and alarm and Immobiliser active won’t start , replaced rf receiver in roof no difference eka code does work and allows me to start vehicle,. Checked for water Ingres slight very slight evidence in fuse box side. Bcu is bone dry. Please help I’m thinking new fuse box. Does power for rf come from fuse box or bcu. Any help please guys