98 gt with digital hvac controls, driver side blows cold air only, passenger side will change with temperature setting. Is this the blending door? there was a clicking coming from under the dash at certain temp settings, took the LH temp actuater off, this stopped the clicking, but still no heat. Does the heater core need to be cleaned, wouldn't the heat not blow at all if the core was bad? I dont know and am about to go nuts. This is my sons car, and he needs it fixed, thanks for any suggestions.