Check the battery as follows:
Battery exterior
Make sure that the battery terminals are not corroded and that there are no loose connections, cracks, or loose clamps.

Brake fluid
Before rechargingGcwr, twr and unbraked twr
Confirm that the gross trailer weight, gross combination weight, gross
vehicle weight, gross axle weight and tongue weight are all within the
limits.
Gcwr*1 and twr*1
*1: These models meet the tow-vehicle trailering requirement of sae
international
per sae j2807.
*2: The model code is in ...