2007 GT overheats when A/C is on (even at freeway speed)

Hey Guys,

Lately it's been getting hella hot here in Cali and I noticed the other day that the temperature gauge creeped up on an especially hot day, (upper 90's). Of course I had my A/C on. Normally my car sits with the temp needle right in the middle, (let's call this 50%) at all times. If it's not super hot out I can run the A/C without any issues. But on this day the needle crept up to about 75% while driving in traffic. When I turned the A/C off the temp went back to 50% after a few minutes.

Last weekend I bought some Water Wetter and added a whole bottle to the radiator. Yesterday again it was high 90's and I noticed that even at freeway speed with the A/C on the needle went up to 75%. Again I turned the A/C off and the needle went back to 50%.

The fact that the temp will go up even at freeway speed has me concerned. I searched around and saw many recommendations for the GT500 fan. But shouldn't the air blowing over the block at speed be enough to cool the engine?

By the way I don't see any coolant leaks. Also I looked at the front of the radiator and there are some fins that have been bent but I wouldn't think enough that would hamper cooling that much.

Any suggestions?

I looked at the radiator through the grill and the hole in under the front bumper last night and I didn't see any debris on it.

But I did notice today that when the car was already warmed up after driving for a bit and being parked, I started it up and the fan immediately came on. I then turned on the A/C because I read that the fan is supposed to turn up to high every time the A/C is turned on and it didn't. It stayed at the same speed it was at.

Maybe this is the problem? The fan is not turning to high when the A/C is on and the extra heat from the condensor is not getting drawn away like it should?

I took the car to a local shop today and they verified that the fan is not turning on to high mode. Is the controller/fuse/relay that handles this part of the fan or is it somewhere else? If I replace the fan with the GT500 fan is that controller part of the fan?

I tried replacing both fan speed relays. Today I tried starting the car cold. No fan. Then turned on the A/C with fan speed on 1 and the fan came on at the low speed I guess. I turned the A/C dial all the way up to 4 and no change to the radiator fan speed. Just in case the fan was spinnin faster and I just couldn't tell I measured the airflow with an anemometer and got about 6 meters/second either way.

What else might the issue be?