A very simple way to find out if there is really something wrong other than your electric fans would be to wire the connection to turn them on to high temporarily the next time you use the car. With both fans running high, check if your temperature still reaches 105 with the aircon off while using the car in stop and go traffic. Do the same with the aircon on. If you do not reach 105 with both fans running high all the time then all you probably need is a resistor or JimFs device to turn the fans on sooner then it previously did. I live in a tropical country and when my aircon is on and just 15 minutes of being in heavy traffic used to cause my temp to rise to 110 easily then the fans would kick in but by this time, the engine is already very hot coupled with the very hot outside temperature, even with both fans kicking in at this point it would take a long long time to bring the temperature down. The solution to my problem was to tropicalize my thermostat which opened at 65 deg, fan clutch which engaged at 90 deg and electric fans which engaged in high at 90 deg. I even installed a switch which could activate the electric fans to high from the dashboard. This is very usefull for very steep uphill climbs and after very high speed highway runs and during summer heat waves. With this setup, even with the aircon on and very hot midday temparatures, my temperature never exceeds 95 deg.
Hope this helps.