megane heater resistor replacement

[DL-C]

Hi. I have recently bought a 55 plate megane 225.
The blowers will only work on setting 4. I have gambled on the fact it is the resistor that's broke and have got a new one from Renault. They want 170 quid to supply and fit.
Has anyone changed one of these themselves so could possibly talk me through the process? Is it something that can be done without specialist tools or knowledge?
Thanks, Dave.

[DL-C]

Well I managed to change the resistor without too much trouble. Unfortunately the blowers didn't work at all with the new resistor on! Put the old one back on and it started to work in position 4 only again!
Any ideas as to what the problem could be?
Thanks, Dave