Jsdirt

I just recently learned from a professional tuner that having an AGM in my truck could be the reason why the OBD-II monitors refuse to run, no matter how many miles I drive it. Every time I try to get a sticker, it comes up as "not ready" - nothing was cleared, and the battery hasn't been disconnected in 6 years. That guy told my buddy (who has a '10 Camaro with nearly 900 RWHP), who was looking to install one to save weight and space, "If you want problems, install an AGM". Yet another reason to steer clear. If it were my truck, I'd just get the measurements of the battery tray and the space above it, and install the largest flooded deep cycle battery I could find, even if you have to go down in size from a Group 78. You might even find what you need at a heavy equipment dealer, used in skid steers, backhoes, etc..

Glad to hear it Dustin!

I'm betting on a bad connection, or ground, that got water in it from the car wash. Any problem that fixes itself is not a mechanical problem. Bad connections and crusty connections are commonplace on modern vehicles now, especially in the salt belt, and especially with miles on them.

I'd clean up the ground wires and power wires (if they look crappy) for the rears. Sounds like you've got a high voltage ground due to a bad connection. It can handle the running lights, but not the higher amperage brake lights.

Good info, but I've rarely seen these GM bandaids work. The ones that have worked seem to have been short lived. Throwing in piston rings WITHOUT honing? That goes against everything I've been taught in my lifetime regarding engine building. I can't imagine being charged $1k labor for that kind of workmanship. With the miles the engine already has, coupled with the high labor cost (11 hours for JUST the shield!!!), and the fact that the AFM system WILL fail at between 90 - 130k miles, you might as well get that thing OUT of the dealership, and into a local garage for an engine swap. You'll thank me later. The other option (what I would do) is to just do what diyer2 said (although I probably wouldn't even bother checking compression given the history of these engines), and swap the plugs, and just run it until something breaks. Either now, or later, it's going to need an engine. Mine is at 97k miles, always had top shelf synthetics run in it since 2,500 miles, and a cam bearing is STILL showing signs of imminent failure. Either wearing, or walking out of the bore. My days are numbered on this engine. Hell, I've already replaced the worn out rear differential, something I've NEVER had to do before on something with less than 250k miles ...

Sorry she went to the dealer. God help you ... It needs an engine - no if ands or buts about it. Common problem with these. Can have any number of issues from rings, to AFM issues - best course of action is to scrap the engine, and buy a new long block from a reputable ENGINE BUILDER - NOT a GM dealership. The dealer is going to do a quick fix - they won't even remove the engine - they'll slap in a new piston and rings from the lower end, and reuse everything else, and charge you a large percentage of what a NEW engine would've cost you at a local, private garage. Seen and heard this same story 100's of times ... Sure, you can attempt repairing it ... but you'll be back to square 1 at any point between 5k & 30k miles. These engines are NOT cheap to repair. Cheaper in the long run to just start over, sorry to say. Welcome to 21st Century auto manufacturing ...

I'd try a hard reset - might get the stupid out of the BCM. Hard reset = disconnecting the battery, and touching the positive and negative cables together for 30 seconds. If that doesn't work, check all powers & grounds to BCM, any connectors, and the wiring for chafe points. If that all checks out, the BCM is probably done for.

Check all the fuses in the under hood fuse panel. I had one blow there 11 years ago in a '00 Jimmy, and I still remember it like it was yesterday. Exact same symptoms.

I'd be looking all around the transmission for broken, or chaffed wires, green crusties inside connections, or bad powers & grounds to the TCM. Also make sure the VSS wiring isn't shorted to ground, or internally shorted.

If you like large bills with no fix, sure - the dealership will be perfect. What solenoids are you talking about? Transmission? Under hood fuse box? What is the problem you are having? Speedometer not working? Service engine light on only?

No problem. I agree - a deep cycle would've been better suited. Sounds to me like yet ANOTHER instance of GM trying to save a buck at our expense. Par for the course today ... Good deal! Let us know if you find one. That'll be valuable info going forward.

Would love to help, but we'll need a bit more info - make, model, year, engine size, history leading up to the problem, what the actual problem is, & miles on the truck, for starters ...

I've been playing around with AGMs in various equipment for several years now. My advice? Save your money. The charging systems of 2007 - up vehicles uses a duty-cycled field, controlled by a computer. Since an AGM at rest is at a higher voltage than a regular lead acid battery (12.80v vs. 12.60v), the computer cuts the duty cycle prematurely. In other words, the AGM never gets a proper charge. I've had an Odyssey in my Silverado for 6 years now. I've had to charge the battery regularly with a 4-stage charger with an AGM specific setting, pretty much since the day I installed it. The OE charging system, plus the normal draw of all the electronics at rest, lowers the capacity of the AGM to a point where you're not realizing the benefits of the AGM. I also had one in my '05 Polaris Sportsman 800, and noted the exact same behavior. You'd be better served installing a higher amperage output alternator. The only benefits of using an AGM, IMO, is in a custom application, like a hot rod, or experimental aircraft - you can mount them in any orientation, even upside-down, plus, you can run a smaller battery than you need, saving space and weight. Now, if you were to install that AGM into a dual battery system with one lead acid battery in the mix, the AGM will be constantly feeding the lead acid battery, causing depletion to happen much sooner. I would HIGHLY advise against doing that. AGM's aren't cheap ... and modern charging systems weren't designed to charge them. You'd actually be better off with an old school "dumb" charging system from the 60's through the '00's running an AGM, but even those aren't designed for it. They're just one notch better in keeping the charge up, since there's no computer pulling back the duty cycle.

I bought a conversion kit for my '86 Grand Marquis back 5 years ago from this place: https://coolbulbs.com/hidkits-body/hidkits-body?SID=vs7caglejftsd8n9qdgrgequf3 Haven't had a single issue yet. It gets driven for 3 seasons each year up here in MA, then is stored in an unheated barn for winter (constant humid conditions). I even have had one of the electronic units mounted on the plastic washer fluid / coolant reservoir (bad for heat dissipation) for this whole time, and that one is still going strong. They are German made electronics, not chinese.

I read about this constantly from fellow techs across the nation. Was happening right out of the gate, too - I saw some with less than 1k miles having issues. GM more than likely wanted to keep a lid on that ... These things are a PITA to replace, too. The connection is a one-time fitting - in other words, any time the fuel rail is taken apart, you get to buy a new one ... and GM smiles all the way to the bank. The only real solution is to find and fix old, or wrecked vehicles - save them from the crusher, and get as many as possible back on the road. Only way things will change is if people stop buying these new ones, and demand quality. Sadly, too many can't be bothered ... which is why thing are the way they are in the world today ...