cooling fan problem?
 

I have a 1995 Hyundia Sonata 2.0 and the radiator cooling fans do not operate as vehicle starts to overheat. Both fans will work when either of the radiator thermo switches are jumpered. Thinking here is the thermo switches have failed. However, two new thermo switches purchased from Hyundai does not help. Fans will not work as vehicle startes to overheat. Will work when jumpered. Most frustrating. The Hi/Lo fan relays when tested are good. I'm getting somewhat frustrated here. Any ideas what is going on?