There is also a little resistor modification that some use to trigger these fans a little earlier than spec..Cost a buck and works well in Southern climates.
It only takes a few degrees difference for 104s to get to that point of high temp run-up at standstill/traffic.
I have always installed a cabin manual sw on any Benz I have owned over the years , just in case I get into a high heat/thermal load condition..hardly ever use it, but it is nice to have ..another simple mod. Simply put a sw across the high side pressure sw and mount it in the cabin, under the dash..
This is a good addition for those who tow a boat/trailor....