Originally Posted by MzLiz
Is that true for an older (1999) F250 too? Asking because on my way down to Vegas this year I stayed overnight in a WalMart parking lot, forgot to unplug, remembered after going to bed, got worried my truck wouldn't start in the morning (it was about 10 degrees out and of course I had the heater running) and had to get up and go out in the cold to unplug it. I could have just left it without fear?
If you want to know for sure, with your TV parked, not running and nothing plugged into the connector, measure between pin 2 and pin1 if you read 12VDC, then you need to disconnect the TT, if it reads 0VDC, the TT can remain connected without fear of killing the TV battery.