The various modules and sensors that direct the top operations communicate via the in car network. The factory head unit uses the same network to control the amp. It is known that the head unit has some functions beyond just being a radio. Warning chimes for instance. What else, isn't for sure. Other car example: Some Caddies display the tire pressure on the RDS display.
The engine and tranny communicate over the net and go into limp in mode if the net is broken.
There are aftermarket modules that connect nonfactory headunits. Those modules also replace the lost functionality. BUT the SSR is too new and few for that market to have caught up.
I drive my 04 to the store, return home and park it. Got up the next morning it started gages don’t move the radio will not come and fog lights don’t work.
Battery tested 12 volts and alternator chick out 14.8 and read 13.8 to 14 at the battery?
My fuel gauge will cycle when the SSR is started then go to correct fuel level, then with in a minute the gauge drops to empty, low fuel comes on, and "range to empty" goes to ---. The check engine light comes on and I checked it with a code reader. The code is PO463 which says: Fuel level...