Need help about Maverick Sport clicking but not cranking

[DALLAS MAVS]

My buddy brought over his 2017 Maverick Sport today in my garage and told me he swapped in a new battery about 3 weeks ago and it's been cranking perfect ever since. But yesterday, when he fired it up, it just clicked once. There was no crank. Okay, for background, I do repairs for Mavericks and this is the first time I encountered this.

After trying it a few times, it finally did start, so we figured maybe just a loose cable or something minor. But then later, we tried starting it again and now it just clicks once every time. You can't get the crank consistently. FYI, we checked and tightened both the positive and negative battery cables already and there's no change. Still just one click.

Thinking maybe the start solenoid is acting up? Could something be draining the battery even when it's off? I don't think it's the starter having this problem/

Anyone run into this before?

 

[arc41]

Got any mods and/or accessories hooked onto the battery? Yeah you might be right, sounds like a classic bad starter solenoid issue. If it clicks once and doesnt crank, even with a good battery and tight cables, the solenoid's most likely not sending sufficient power to the starter.

 

[maverick.city01]

Even with a new battery and tight cables, a failing solenoid can just click and not send power to the starter. Could also be a weak connection somewhere in the starter circuit or a parasitic draw
Test the solenoid first anyway