I put it into gear and it dies.

Bewy said

If 12.3v at the battery was measured with no load, then the battery is on the way out. Might be worth buying a new battery before it fails when you are away from home.

Click to expand...

:rofl:

If you had read more than a random line, you'ld know he'ld been f'in around looking for an open in the run circuit.
Regardless, before someone runs out and buys a battery, the first thing to do is use one of these.