Stuck bolt on cab shocks. Will I have to cut them?

Truck won't start. Can I buy one battery or do I need all four?

 

Thanks again every one. I jumped it thru the alternator. And what I believe to be the starter ground. Will post the storey some time Tommrow. Gotta hit the sheets. 2 30. Will be here in no time.

 

Ok. So onto the batteries.

Last summer the bunk a.c would just randomly shut off. I blew out the filter, than after a while I just learned to deal with it. I'm still trying to figure out if I have a safe trip or the other unit. I never thought it could be a weak battery because the bunk heater never died just the a.c.
Fast forward a week or two. The truck barely started. But it did, it jumped to life. I made a mental note to not forget to shut off the main power again. After warming up and traveling about a hour. All the lights where super bright, and the bunk a.c. not longer cut off. So I thought to myself all it needed was a good charge.
Fast forward to last week. I had worked the key on and off to raise and lower the cab to put the shocks on. While tightening the last cab shock I asked the Mrs. To turn the key off.
She did. But unbenownest to me her or my self, she went one click past off. And it sat like this for about 18 to 24 hours. Causeing another no start.
I took the two batteries not connected to that little box to a local store and asked them to charge them for me. They called about two hours later stating one battery was no good. But the other was fine.
But this store always says that about my automobile batteries. Case and point. My pick up truck still has the same battery they said was junk 3 years ago.
Fast forward to yesterday, and I don't know what made me think of this, or why I didn't think of it sooner. When the bunk a.c. cut off. I flip the key and the dash volts read 13.2. Of course I started it and keep it running untill it went back up to 14.1.
Sorry its a long post. But you now have all the indo I have. This truck has 4 batteries. A small electrical box is connected to the front two. Then those two are connected to the back two. The back two are the ones that went to the charge shop.
Please advise, do I test them with a voltage meter. Or just break down and buy batteries? To date. You now have all the info I have.
Thanks in advance

 

Thanks I will do that.!
On then 12 volt out let are you talking about the GPS/phone plug in or a regular plug in.?