As the battery voltage drops, the current increases on the slide motor or any other device for that matter. There is a good chance the low voltage caused an overload condition and blew a fuse or circuit breaker protecting that circuit. Next time, start the tow vehicle and plug in the towing umbilical to support the TT batteries if the batteries get too low.
Here is a
Meter you can plug into a 12v outlet and keep an eye on the batteries.

Letting the battery voltage drop below 12.00Vdc(50% charge state) will shorten the life of the battery.
Here is a 12v battery voltage State of Charge chart:
12.6+ = 100%
12.50 = 90%
12.42 = 80%
12.32 = 70%
12.20 = 60%
12.06 = 50%11.90 = 40%
11.75 = 30%
11.58 = 20%11.31 = 10%
10.5 = 0%