Problems with temperature display

Hello together, have had problems with the temperature display of my V50 Momentum 2.0 D year 2006. And indeed the temperature display spins, this at the moment always shows temperatures against 0°C. Have already researched and got out, that in the driver’s door is a plug where the whole cable (also of the temperature sensor) runs from. The connections on this plug oxidize and thus it comes to these temperature jumps. The remedy is to renew the plug, but this is not so easy there several wires run and it has not even been done. This is a cost-spiile thing, if it is because it is! Does someone already experience this problem here? What can you do? Try to clean the plug with spiritus, maybe it works.