Cooling fans not working

I have a 1996 gp, with the 3.1 motor. The car ran hot, and blew the head gaskets. Lucky, my dad replaced the blown head gaskets, but the cooling fans will not come on. We have checked relays, and the fans still will not come on. The only way we could get the fans to turn on is by turning on the AC. If any knows a what the problem could be, please reply back. I don't want to blow any more head gaskets this winter.

Thanks,
Dave

Might be a coolant temp sensor.

Well you can check the low coolant sensor. I have a 94 SE and the fans(as the PCM would think) were starting at 180 but the heat gun said 210. I replaced the low coolant sensor and it working beautifull now.