truck just clicks when try to start it , which battery is the primary battery?
Did you check your owners manual?
no i dont have one!
Check online. I am sure Dodge has everything you need on their website.
no i dont have one
generally the one that has most wires connected at positive lead/terminal is the primary but check all terminal and connections at batteries for clean and tight. If you still get the click, try turning the key to on and jumping the solenoid. If it starts, the solenoid is bad. That's a good place to start with and very commonly the problem found for any vehicle.
Looking for a Used Ram 3500 in your area?
CarGurus has 2,193 nationwide Ram 3500 listings starting at $4,993.
Search Dodge Ram 3500 Questions
Dodge Ram 3500 Experts