Hey guys, i have a 2005 gmc yukon with electric fans. It is the 5.3 and the electric fans will not turn on. I have replaced the coolant temp sensor and the relays and it is still inop. If i send 12v to the fans they will turn on and constant power is getting too the two 4 prong relays my tools will not fit to test the 5 prong. None of the fueses are blown either and relays have resistance to them. It has a slight hickup on startup but not much of one and sadly no they do not work with the ac on the temp will go straight past 210 when parked