What I know:
Relays and fuses are good
Coolant looks good and the tester says its still protecting the car.

What I don't know:
Are the sensors good, the are not throwing codes unless I unhook them.
Are the grounds good, due to the way they wire the fans I am not sure..

Trouble shooting.
There is power at the fuses and relays, but I do have backup new ones that did not make a difference
If I turn on the AC the fans do come on.

Research:
With the AC on the fans are in low power, they run this way by running the fans in series to reduce the power to each fan by half.
The fan will not come on when the car over heats.

[This message has been edited by Jake_Dragon (edited 07-09-2022).]

Can you scan 'live data' with a reader, or are you using a digital meter? To check the sensors with a meter, you might wish to measure the voltages of each ECT with the key on, both when the engine is cold and then when it's hot. You can measure at the processor, or the sensor. There probably will be 2.5 to 4 volt swing somewhere between .5 and 4.5 volts across the Green and Black wire for sensor 2, and between Rd/Wht and Grn/Yel for S1. Both sensor grounds (Black and Grn/Yel) should have absolutely no voltage on them, key on. The sensors may not swing across the same range. And use only a digital meter, not analog, because it's input needs to be very high impedance as to not influence the readings.

Right now I don't have a way to check the sensor. My reader does not log this data that I am aware of.

Have not had time to work on the car as its been miserable hot, I hope to have time this weekend to pull the thermostat and flush the system and see if that makes a difference.

Wanted to circle back to this.
Something about looking for zebras when there is a horse right there.

Changed the thermostat and the car is back to normal..

quote Originally posted by Jake_Dragon: Wanted to circle back to this. Something about looking for zebras when there is a horse right there. Changed the thermostat and the car is back to normal..

Good to hear it was an easy fix.