Good morning everyone. I am working on a friends 2.8L Firebird. The radiator fan is not activating when the vehicle reaches temperature. Thus I did the following, since this car is actually OLDER than the guy who owns it:

1. Replaced Relay
2. Verified 12V at the fuse panel for the fan
3. Verified the radiator fan motor works with direct 12V attached (a little sluggish, but I did make him buy a new fan motor)
4. Took a voltage reading from the 2-prong connector for the temperature sensor and got 5V
5. With the ignition switched to the "ON" position, reading a 5V signal at the connector, with a known working Relay and 12V at the fuse, I close the loop at the connector and no fan, with the new fan motor too.
6. Verified junction box, no shorts.

I am thinking the ECM/ECU may be shot to hell?