Engine/Transmission (1998.5 - 2002) Fan never kicks on ??

[Turbo Terry]

While pulling hard up grade my 99 got hot. This is because the radiator needs to come out and be cleaned due to the fact that the crankcase breather hose WAS to short for many miles before being longer and my RASP belt was to tight taking out the shaft seal making a diesel mess. Anyway buried the water temp gauge- check engine light and bell. But the fan would not come on like the southern boys talk about when pulling hard and hot. Whats the problem?? Thanks

 

[Turbo Terry]

Also had a bug screen in front of radiator and transmission cooler which I removed. 75 degree day major climb.