99 xj 216600

over the life of my xj I've had Way too many batteries. I replaced one (interstate) a few months ago, the shop said it was good, I told them my starter was new and they needed to put a load test on the battery, it failed. The replacement was promptly handed over and this was 6 months ago. That's interstate 3 or 4 over the years, but I do not know that it's not the vehicle.

this week she starts weaker daily until hardly at all.
been there done that, but this is WAY to soon to be replacing a battery again. There is black residue in-between the caps which I'm contemplating if some thing boiled over, or just bumpy wheeling has allowed some to leak....

today I bought a Duracell agm battery to try something new, but I need to check the system to make sure it's healthy so this battery doesn't die!

Directly connected to the battery:
. starter 6 months old, New, not a refurbished
. All cables newish 1 awg, soldered hand built
. Alternator napa 1.5yr old, multimeter shows healthy charging at idle or reved 14v
. Light bar with its own fuse- relays
. Head light harness, fuse, relays...
. Arb pump and locker switches, again on their own relays + fuse, wired in to key on.
. At one point had an aftermarket stereo stolen, now its stock with no loose wires that I've seen.
. Winch with quick disconnect, left unconnected unless needed.


My question to you all is what should I be checking for, in what order, and is there anything other than a multimeter for tools that ide need?

In addition I had a battery temp sensor code in the early summer, so I could use the Mopar part # if anyone knows it, I want this replaced just in case.

 

the ground looks new above here, just a dirt layer on the outside that crumbles off leaving a healthy looking ground strap, maybe remove and clean for good measure? It's for road noise anyway right.