1991 LS - Blower motor works on all 4 speeds. But the control panel selector (push button) for where you want the air to flow will not change. You can push the buttons but there is no air out of the defrost, panel nor floor. The motor that controls the flap door does work. According to the manual it looks to be a ground (G381) problem. As all three components - master control, deflection motor and recirculation motor do not operate per the button pushed on the control panel. Any idea where the ground is located? It is commonto all three components.
There is a teg tip about this…you can try resoldering the contacts