What did you do to your bus today

[dentmac]

Hi,
I have a Lincoln MKX and after several boosts, I put in the charge wire and Lincoln (Bless them ) put in a new battery.
Crazy thing still goes dead occasionally. I've pulled it 2 days without issue several times, but last week it died after 4 hours towing. (And I had started it the night before after stopping for the night.)

When I first got the car , I called Ford.. Four down towing is allowed , so how to fix this?. They never heard of that happening ( even though it is all over Google) They suggested a wire from the coach, and inverter and a charger!.. and that doing that would invalidate the warranty ! )
If it was power to the PS pump.. wouldn't the PS still work?

R