There are several threads about similar issues, do a search using forum's tool. Summarizing, I'd see at thermostat, fan relays (there are one for low speed and other for high speed), or a blockage in coolant tubing system.
You don't actually say whether the temperature drops back down when the fan kicks in. If it does then it is highly likely to be an electrical fault and you would be really better either investing in PP/Diagbox or finding a local member who can plug one in as you will probably save time and money by doing this. If the temperature doesn't drop when the fan kicks in then the problem is more likely to be mechanical as Erick has said.