On my 300SD I have modified the cooling system wiring for better performance in my hot climate (so calif > 110F) I removed the a/c cutoff sensor above the thermostat, and connected the wire to ground. Next, I installed a 100C Temp switch above the thermostat and wired that with my A/C high pressure switch.
As a result, the fan now comes on >100C or when A/C pressure high.
Is this a safe wiring modification in your opinion guys. Its worked for me for quite some time, but I would like others opinions on it.