Caravan Fans will not come on

i recently had a bad thermostat and replaced it. Now I have a larger problem the cooling fans will not come on. The temp gauge is slightly below 1/2 way and I have checked the fuse under the hood and jumped the fans to make sure they work. I know the temp is getting too hot by the smell of anti freeze and when idling for 15-20 minutes the fans never kick on.

Could this be the temp sensor? The temp never goes above the 1/2 way point.

All help will be appreciated...

I had a simular problem and replaced the fan relay which is located on the bottom of the left front frame rail just behind the facia.
Unless the a/c compresser is on, this time of year my fans rarely come on.
You could have spilt a small amount of coolant which is causing the smell
My van is a 98