[TCMdocs944]

Do a search of posts for "fan switches, thermoswitches, cooling problems" etc. There are a few great post that should fix the problem.

I think this is a great place to start on improving engine function/performance.

(hints)
get both fans working
change thermofan switch to a lower temp
change thermostat to lower temp if your brave
bleed, burp or whatever the system
if this fails to get both fans working ....
relays(do search)

This stuff is not $ intensive and fairly easy stuff. Just takes a little time and about a six pack.