Here's the issue. I was working night shift a couple nights ago, we came in early due to the cold (-40) and a few hrs later I started my truck and let it warm up for a bit and when I came out side there was smoke billowing out from under the hood. It was my passenger side battery that was smoking. I thought I happened to be a frozen battery so I installed 2 brand new batteries. When I started the truck, it ran but it wasn't really charging (the gauge was on the bottom end of the green). So I figured it was the alternator, so I put in a new alternator. I started my truck and the passenger side battery blew up in under 3 mins (literally the top and side blew out). What do you guys figure? ECM maybe?

 

Sounds like your crossover cable that goes from the passenger battery, over the radiator and to the driver battery is corroded. Likely all of the cables are corroded. Corrosion tends to creep under the rubber jacketing and into the stranded wires. The charge rate is controlled by the driver battery, if it is weak and not charging, the ECM cranks up the output of the alternator and thus fries the passenger battery. I recommend you clean all of the cable ends as well as all of the grounds that connect io the frame and body panels. These trucks need clean power to operate properly. Clean or replace the cables.

Make sure the cable ends are tight and do not wiggle at all.

 

What he said or possibly a loose or dirty battery terminal connection.

 

On my 04, had oil changed at wally world, part of service they clean battery cables, unknowing to me they leave the positive cable loose on driver's side battery. Loan truck to son, get call truck won't start, check cables find loose post clamp, tighten clamp jump start truck, weird thing happen, go to auto zone as wally world was closed' right battery was cooked drivers side carried 4.5 volts, after two new batteries all is Ok, so check battery cable for cleanness and tightness regurally

 

Did you inspect the cables when you initially changed out the batteries?

 

I'd go a step further with the cables and resistance or load test them with a multimeter. Get an actual number and verify they are still good on the inside at conducting. It's real easy to make the mistake that the cable looks good on the outside, but the inside it is 'clogged up'.

I just did the battery dance a couple weeks ago these procedures are all fresh on my mind (I went by the manual even! lol). I would like to replace the Pside neg. cable as the clamp was a little out of whack and I don't want it surfacing as an issue down the road.

 

So I finally got back to my truck today. I put on a new crossover cable between the batteries, I didn't hook up all my accessories. When I started my truck it ran fine. I attached my accessories including the relay/solenoid deal right beside passenger side battery and it started acting up again. Once I disconnected the relay deal it ran fine. What is this relay deal called so I can get a new one.

 

Can you provide a photo of this?

 

Its your grid heater relay. Check the cables going to the block under the intake horn. Look for a chaffed wire.