But, how much are the odds that both systems are having a problem at the same time.
Excellent. At least someone is thinking on this forum.
Pin #8 from the AAM is responsible for grounding relay #26. And the system works as follows:
1. During normal use of the veh. without AC, the Coolant Temp. Sensor and the ECM monitor coolant temp. When the coolant reaches a predetermined degree. it will send a CAN message to the AAM to turn on the aux. fans, via pin #8. When the coolant reaches another predetermined degree, the fans will be turned off. And so on , and so on.
2. With the veh. in AC mode, the AAM is the only thing responsible for turning on the fans, via pin #8, when the Refrig. Pressure Sensor reaches a predetermined pressure at the sensor. And so on, and so on.
Although the same grounding pin is used for either grounding, they are actuated by different means. And therefore both the Coolant Temp. Sensor and the Refrig. Pressure Sensor would have to be faulty at the same time.
But in any event the Coolant Sensor is working correctly because it is showing high temps. on the cluster.
Yes there are tests for the Coolant Temp. Sensor but it involves testing both at the sensor and the ECM. Back probing of the ECM and DVOM will be necessary. Let me know what you want to do with these tests as I will have to set something up in another post.
In the mean time, pull up the fuse/relay module out of the box and look for the 4 numbers affixed to the AAM. The number will be 163 54 xx xx. Start hunting on line for the same exact number.