Ford mustang 2005 v6 proble is that the cooling fan only turns on when max ac is turn on, I ran the vechile for 45 minutes with out the ac turn on and i stoped at gas station to check if the fan was turn on and no it wasnot but the temperature gauge was in the middle and the antifreeze was normal any suggestions

The info I looked at was for v6 engine. The fan turns on at 105c or 221 f. If engine is overheating, I'd want to know, how hot in degrees f?
If you turn on ac, the fan may run? The ccrm controls the fan. Check for applicable cooling fan trouble codes? Don't replace anything unless your testing points in that direction.
It may be possible to use jumper wires from battery to connector that goes to fan, for voltage and ground, just to see if fan will run. If it won't run, suspect fan itself. Just to be safe, you might use inline fuse on jumper.

First, test your tps with a multimeter to make sure it is good. Explorers and mustangs are knownto go through them every decade or so. Reading should be smooth from no pedal all the way to wide open throttle.

If the tps tests ok, the relearn procedure is simple. Disconnect the battery for 30 minutes or so. Reconnect the terminal and start the engine. Just let it sit there idling for 10 to 15 minutes. Then turn the A/c to max cool on high fan for a minute or two. Drive around and see how it does. You can turn the ac off or not. The end.

to reset an ECM (CPU) program it will be necessary to use a scanner tool. The idle program is already in the cpu so all it takes is to reset the corrupted cpu program

Ck timing

From the symptoms you describe it sounds like the computer may not be getting the signal to turn the fan on so the temperature sending unit may be bad. The computer regulates the fan speed when using the A/C, the fact that the fan turns on under those conditions indicates that the circuits to the fan are most likely the problem. The fan has a high/low speed. There is a resistor assembly mounted in the radiator, that senses the temperature. If it is broken, this will cause the issue you're talking about. Pull it out and give it a look. I'm betting it's corroded or broken. The part number is 1R3Z-8L603-AA. Should run you around $40-45 from your local Ford dealer. Also make sure the rest of your cooling system is good shape, radiator clean, inside & out, thermostat working properly and a clean mixture of 50/50 coolant to water filled to capacity. Good luck, i hope this helps.

the fan not coming on unless you turn the a/c on is a clue.this tells you the fan is working but the coolant sensor for the fan operation may not have been the one you changed(as there is one for the dash gage/light and one for the computer to turn on the fan).also the fan relay may be the problem not turning the fan on without the a/c on.

Scan tool or put it in a pot on the stove,with a OHM Meter hooked up

The engine cooling fan only comes on after the engine reaches 225-235 Degrees F, that is well past the middle of the gauage, so u may not see it come on very often, unless the engine is overheating there is nothing to worry about here

the clpicking is the compressor for the a/c. If you turn your steering wheel left or right does the key come out? When did you have a tune up?

Make sure the radiator pressure cap is the correct one and that the hose is not soft--check the lower hose and heater hoses for softness as well. They should be firm, but not hard or cracking. The temperature sensor is reporting normal operating temperature, so it and the thermostat are working correctly (hot water would blow out of the radiator if it were stuck). Check the cooling fan for free turning and no noise. Check it's grounding connection. Check the fuse box for blown fuses to the fan and to the A/C compressor. Make sure all the relays and fuses are firmly pressed into their sockets. Check the A/C compressor clutch winding for resistance--should not read infinity. Does the blower motor for the heater/A/C run when either is turned on? The A/C switch on the dash may be defective.