Checked all fuses, fine, electrician has checked all the earths, fine.

Had a look around the fuse box and no damp but not removed to see for dried joints. Everything I have looked at points towards this. Someone offered to put another live cable into feed the heater fan but that is just cutting corners and I really dont want something else to go on the fuse box and cause me to be strandad somewhere or the fuel pump etc stops working