Originally Posted by Atoy
These vehicles have the terrible electronic fan clutch that apparently was so troublesome that GM abandoned it and went back to a mechanical fan in 2008.
My 2004 TB will not pull a small camper in weather above 80 degrees without overheating and I tried almost everything, including a overhaul of the entire cooling system and exhaust. The only fix that finally worked was a Fan override that requires bypassing the computer to force the fan to run full speed.
Someone said they put a 2008 mechanical clutch on the 04 and it worked. I have not tried that one.
I have similar issues since I put in a transmission cooler. If it is above 80 and I am not moving the temp goes up. New radiator, water pump, thermostat, temp sensor, fan clutch and hoses. Turn the AC off and it helps but the temp still stays higher than normal until I get moving again.
The trans cooler is not blocking that much of the radiator but it must be just enough to reduce the airflow. I suspect there is a computer problem that is not triggering the fan to increase speed. I had one shop check it out but their scanner would only say it was operating at the right speed at idle (700rpm I think).