2001 megane electic fault

i have a lovely old 2001 magane 1600 16v..which is running fine.. the problem is the wipes have stop working on inpection the linkage has cut though the wiring and blow motor ..I have had motor replace and wiring done ...but they still not work ..checked motor and is fine ..I am told that a electric fault on some piece of kit ..which is responsible for working all aux etc I am told that it will be about £500 to buy and then coded by Renault another £200 which is more than car is worth ..but I don't want to scrap as she is a great low milage car an runs fine ... what can I do cant run it manually has to go though this unit ...don't know what it called ?? ideas please..the rest of car runs fine just no wipers .help please is a second hand one the way to go then have it coded by Renault >>help me please