is cooling fan "on" temp adjustable?
 

2005 v6, automatic. all stock. is it possible to adjust the temp at which the cooling fan comes on? i'd like mine to come on sooner. if so, where can i find this procedure.
i'm in phoenix arizona and this car will need all the help it can get to make it safely through our summer temps. thanks

Tuning, it is, but not normally. My tuner has an option to change when it comes on
in increments up or down, but I can't enter a value, just turn it up or down.

Doesn't matter WHERE you are, if the coolant system is healthy, then you don't
have to worry about anything. If that were the case, then they'd sell cars in that
area with a lower on setting for the fan(s). Mine only has one fan, and I have an '08.

Also, it does not matter, the thermostat sets the bottom line as to when it opens,
so if you REALLY want to run cooler you need to sway it out for a 10 degree lower
one. With this is mine, that does not set the CEILING for the temps, you can still
climb to over 200 degrees.

is it possible to install a manual switch into the fan circuit so that i can turn the fan on whenever i want to?

You bet:
https://i93.servimg.com/u/f93/19/84/61/93/20181010.jpg
I made this, but never used it... Can use it for line-lock, fog lights, or another
relay to put the cooling fan on.

If you install a manual switch and do not use a separate relay to turn on the fan, as 08 suggests, and turn on the stock relay, this will likely tell the PCM that the fan is failing to turn off, and throw a trouble code & CEL.

You can use the switch to latch the factory relay, no problem WHAT SO EVER. The SJB won't know
that its already on when it turns the fan on. The SJB provides a ground to the coil when the ECU needs
the fan on. You're doing it manually, so it's already ON when the ECU commands it, so it will STILL sees
it as on. The COIL side is not what provides the power to the fan, the coil turns the relay on, and
voltage passes through on completely separate terminals.

The only way you cause a failure, is if you loop the factory coil supply though the switch, so that when
the switch is off, the relay won't latch because you have the switch off. NO, no, that's not how we are
doing it! You are providing a separate ground for the coil, to trigger the factory relay when you see
fit. So, when the switch is off, it will NOT interfere with the normal operation. When the switch is on,
it still won't interfere, because IF the circuit is monitored, it already being on, when the ECU commands
it on, won't make a bit of difference.


https://cimg6.ibsrv.net/gimg/mustang...26831771e6.jpg