so ive noticed a couple things... im not 100% sure that my fan speed settings are all working properly. obvious the high setting works, but as you turn down the heat- theres really no distinction between the 1-3 settings. any thoughts?

also, when i turn my HVAC system on and off theres a loud pop/snap sound under the passnger side of the dash- kind of like my jeeps telling my its officially turned its HVAC off. it started a couple months ago..