have you checked the fan plugs, as my 2.5td was overheating ,so i did all the realay checks, nothing all i could get was one fan comming on full speed ( uk passenger side) when it boiled up, it was the (uk drivers side) plug on the fan itself , as they run in series at normal conditions and then in paralell at high temepratures, someone posted a very easy to follow circuit diagram of the fan wiring, on this site, or the XMLsite, i cant seem to remember who it was though,,,,, ,,terry