the sun load sensor is at the top of the dash, chances are very slim they could have affected that with audio work. also, it doesn't affect the regulation of the interior temp all that much, it's a secondary load sensor & has an influence but I don't think it could even cause what your talking about. same goes with the outside one, it is just a load sensor but doesn't affect the regulation to the point of it acting the way yours is. that one in the knee bolster is the main sensor.
do yourself a favor & check behind it, make sure the electrical plug is plugged in and also there is a rubber hose that also gets connected to this which goes to the hvac system... this hose has slight suction & causes interior air to draw over the sensor, otherwise it would just measure a stagnant pocket of air, which is not a good indication of interior air temp... that hose needs to be connected for it to work right... it is very easy for someone to replace this panel & miss this hose connection, it's just a slip connection, no clamps or fittings or anything... the sensor is nothing more than a thermistor which rarely goes bad, I'd bet on the plug or hose being disconnected before betting on the sensor itself failing... yeah it's a good idea to blow the dust off of it but no need for electronics cleaner there, electronics cleaner might stain something, to do that you should remove it anyway I'd say but really no need...
