'99 Xantia 2.0 Hdi blower fuse F21 meltdown

[Edhertz]

Can someone please put me right with this age old chestnut. Blower fuse F21 decided to go into meltdown recently. After cleaning the melted mess up and cleaning the fuse holder wipes, I replaced fuse but it soon overheated when blower was run. This is what previous contributors have described as ‘contact black death’ or resistance thermal runaway so set out to bypass. Motor’s been out, runs fine and gives reading of approx 20A. Green blower relay (Cartier 12v 35A 03531) pulled, checked and works fine. I bypassed F21 by connecting a 30A fused live feed from the non switched red wire feed to the ignition switch to blower relay pin out 5. This according to the schematic should result in the fan booting up but …. no joy. The only way I can get the fan to work is by replacing F21 which makes no sense according to the schematic in Haynes and shown on this forum. Pretty sure wiring’s not been got at by someone else,
Thanks in advance.