Just to clarify, and your model MAY be different, but on US models the low-speed fans do not actually come on exactly when the compressor does, but instead when the AC refrigerant pressure exceeds a certain level. In cool weather, they may not come on at all; in warm weather, they will probably come on after the AC has been on a few minutes. There is a pressure switch in the receiver-drier which you can jumper and if your relay, fuse and ballast resistor are OK, the fans should come on low speed.
For more info, do a search on "aux fans" and you'll get lots of info.
On the other hand, if your coolant temp is getting near the red zone, I'd suspect there may be something else at play (partially occluded radiator, bad thermostat,etc.)