Alright to make it clear this only happens in the summer under hot weather conditions. I noticed last year my car will get up to the A on NORMAL but never rise past that. I did notice it had threw a code for one of the fan speed sensors I just can't remember which one it was or how I go about fixing it, help?
Well first off the stock temperature sending unit sucks so don't trust it. Mine was usually stuck on the A as well when the car was running just fine. I now have an aftermarket temp gauge in my car and it stays posted at around 200 while cruising. I don't even bother with the stock gauge. As far as the fan, check the ccrm. It controls the cooling fan relay. But make sure you figure out which code it's throwing to be sure before you go spending money.
Well I know its not the sending unit because when it warms up the a/c warms up as well but I had the code checked today and all I had was a code for my deleted cats
I'm not sure about the mod motors but the 5.0's have 2 temp sensors. 1 for the gage and one for the computer. at least get a laser temp gun and read the temp on the rad hose to find oout when the fans come on.