We have a 2003 jeep liberty 6 cyl. 3.7L w/one fan that was over heating and I researched all the answers to others with similar.
I replaced the radiator because of a pin hole leak and changed thermistat.
Water pump is working, heat and circulation is good.
Fan was running after install of parts listed above (didn't realize how slow).
Over heated in stop and go traffic again.
Took apart fan motor electric connection at the shroud, started the engine, 0 volts, engine got to 100 deg., I got 5.6 volts, remade the connection, fan did not run.
Hot wired the fan to the battery, the fan ran fast and strong. BINGO!!!!
Could not find reference to the proper relay, buy luck I removed the blower motor relay, the voltage went to zero. There is an exact match next to it, turned the engine off, swapped it and the voltage went to 12.6, BINGO!!!
BAD BLOWER RELAY !!!!!
Chrysler/Jeep part #4727370AA (old #56006709)
Thats my fix, hope it helps you.