Radiator Cooling Fans

I have a problem with the maxi fuse (40A under the hood) for the radiator cooling fans blowing. The fans work fine until I turn on the A/C and then the fuse blows.
I installed two new relays (one for each fan) thinking that might be the cause. This did not fix the problem.
What else might I try?
One other clue is that the tempature light does not come on when the system overheats. The TEMP light does come on during the usual testing of the lights/indicators when you first start the engine.

Disconnect one fan ( if 2) at a time see if the fuse blows. BTW always post the year.

Thanks I will give that a try.