What a mess....
Have you tried running 12v straight on the fan itself...? Might be an idea first, hopefully it could save you a lot of hassle.
As I said in your resto thread, mine was full of shit and blew fuses constantly, cleaned it out and its been fine since.
If you do find its the fan that is broken, its the same as normal mk5 Escorts. No idea about cars with A/C though, I know they are different, but no idea what...