So have very little heat in my 2003 SLE with 98,000 miles with auto system. Temp gauge is good, top rad hose very hot, upper heater core hose hot and lower hose fairly hot.
What I have done:
1) Run motor at 2500 for 10-15 sec multiple times to try and clear any air from heater core.
2) Checked that radiator is full to top with anti freze.
2) Recalibrated actuators
3) Removed glove box liner looking for air temp actuator but not sure what I am looking for. There is a eletrical motor type box on left with a small silver shaft end that does rotate when I change temps for either side. Did not figure out a correlation. Seems this is not the correct one.

Seems I still neeed to find air temp actuator and check and/or my heater just needs flushing. Any thoughts?

Check out this thread:

https://www.gmforum.com/bonneville-g...r-side-296028/