So I've had this truck for about a month, I had gotten the water pump and thermostat replaced already. The truck has had problems starting in the cold, it would take about an hour to jump it every morning. Also, my "Wait to Start" light stopped working about a week after I got the truck. Yesterday, I had jumped it in the morning, went into work, started it just fine on my break, let it sit for 30 minutes to warm up so I know it would start when I get off work at 7. So, I went out to the truck after work, and it wouldn't start. I had my uncle come jump me at work, and then this happened. The wait to start light popped up, the "check gauges" light came on, my radio suddenly did not turn on(It was working on my lunch break), the battery would show it had about 12 volts but then would creep all the way back down like it had a drain. What I'm wondering is, should I just get two new batteries or is my problem bigger than that? I got it to slowly crank once or twice last night but called it quits. Another thing, when I went to start it (while being jumped) there was a continuous noise coming from the engine bay, and it looked like a "Fuel sender"? You can see it in the video. But that sound didn't go away until I took the terminal off of the battery. There are also two wires, red and black, ontop of that, which are cut. You can also see that in the video. I think once summer comes around I'm gonna try to unload this truck and go back to a gasser.

 

The noise is likely from the electric fuel pump. It should only run during cranking or with the engine running. There might be an issue with the fuel pump relay that causes it to run continuously which would explain the battery drain. The cut wires are from the fuel heater inside the fuel filter which isn't super critical but it might be worthwhile trying to figure out why they were cut.

 

Might charge the batteries(not using the truck) to a full charge. Then load test them the next day and see what condition they are in.

 

Agree with Moparite, try to get the batteries fully charged. I recommend a BatteryMinderPlus, I've had mine since 2013. I've resurrected quite a few batteries with mine, it'll supposedly removes sulfates from the battery plates enabling the battery to take a full charge. Since its winter, I'd remove them both and put them inside where its warm. Wire in parallel and let it go for as long as you can.

Next I'd check to see if you have a drain on the battery when you shut down. Its called a parasitic drain, I just pulled the first link I google came back with:
https://www.wikihow.com/Find-a-Parasitic-Battery-Drain

 

I found that the grid heater was stuck on after the key was turned, so I followed the instructions on this video on youtube, I just tied back two of the cables, and got a new battery. Started up after about two minutes lol. Thank you!

 

sounds like your alternator is not charging and draining the voltage . if you can load test the batteries.they sell a load tester at harbor freight for 19.00