We go more off of EGT's than the actual engine temp. 1200rpm is where mine runs too. Fan should never need to come on sitting there idling anyways. Only time my fan ever comes on is when I'm working the truck and it's really low on coolant.

 

My fan come on but I just had whole engine wire harness replaced a mouse ate wires. Now it comes on at high idle and sometimes just idling regular.....does computer need a flash maybe?