Note: I posted this here because I saw the name Trailhawk in the description but now I see that this is for older Cherokees. But honestly, scrolling down the sub-forums, I don't see anything for 2017 Cherokees, so feel free to tell me where I should post this.

A couple of days ago I tried to start my 2017 Jeep Cherokee Trailhawk and the dashboard started flashing and doing things like when in movies a car is stopped by aliens and the occupant is about to be abducted. However, I wasn't abducted by aliens, and the car kind of died after this. The battery doesn't seem completely dead, as the instrument panels are still on, even the front lights are on. But I kept on trying with the same result. This is a car with 37,000 miles on it, and a little over four years old, so needless to say, I'm not the least happy about it. But I'm trying to avoid paying an expensive tow truck to my mechanic, and the first thing I want to rule out is that it's the battery. So my wife bought some jumper cables, and then I learned how you're not supposed to connect negative to negative, but negative in the working car to a ground point in the dead car.
Ok, so I open the PDF manual, and it says "Connect the opposite end of the negative (-) jumper cable to a good engine ground (exposed metal part of the discharged vehicle’s engine) away from the battery and the fuel injection system." What the geniuses that wrote this manual don't know is that most people are not mechanics or car enthusiasts, so how the hell am I supposed to know where that ground point is? I mean, I can tell where the engine is, where the battery is and maybe a couple more things, but the engine compartment has lots of pipes and stuff coming in and out of places, and I spent several minutes inspecting every inch from over the engine, I didn't see any obvious point to connect the negative cable. I would connect it to the body of the car, but even inside the engine compartment, everything seems to be painted. Even the parts that don't have paint in them, have other things hooked to them, and not being a mechanic, I don't know if connecting the negative cable there might fry a component, or ruin my car or even worse, ruin my wife's car, then we're both screwed.
I'm attaching a couple of photos I took from the engine compartment. Can somebody please tell me where's the famous "ground point"?




This is what's inside when you take out that big cap from the plastic engine cover. There's a nice metal part there that would seem to me like a good place to attach the negative cable, but not being a mechanic, I don't want to take a chance that could be very expensive if it goes wrong.

You attach the cables to the positive and negative terminals/posts on the battery. The same on both vehicles.

No, you don't, unless you want to risk damaging your car or even an explosion. Hell, that's about the first thing you learn after doing a quick online search, not to mention the manual itself:

"Do not connect the jumper cable to the negative (-) post of the discharged battery. The resulting electrical spark could cause the battery to explode and could result in personal injury. Only use the specific ground point, do not use any other exposed metal parts."

To expand upon that rationale, the reason there is a danger with the posts being used on a discharged battery is that a low-charge battery is apt to produce hydrogen gas or hydrogen sulfide gas that can especially be true in event that the battery was overcharged or overheated. THe gas would usually have a smell, yes, but the amount needed to combust need not be a lot, and the open hood of a car sometimes with atmospheric conditions can be perfect for it to stay in the small area instead of dissipate. On a worst case scneario, attaching to the discharged battery with the ground lead (which should be the 3rd overall in a jump start, last on the vehicle needing a jump), may produce a spark when connecting. That spark, normally, would do nothing. But in a theoretical situation where we have a discharged battery with a small cloud of hydrogen/hydrogen sulfide gas around it, we may ignite an expolosive gas that theoretically could chain back into the battery or at-best just outside of it. There arent many situations where an explosion is okay as long as its small, usually an explosion is undesirable and the bigger is just considered worse.

on an AGM the tendency to gas off is Less, but you cannot escape the possibility nor should you act as if its not a possibility. The occurance is low, but take it from someone who has scars and is lucky as hell there was a tractor fender in the way of their face, batterys blowing up are not fun and the damage to YOU is going to something because youre most likely going to be facing the battery, with hands near it(in hooking up the lead), and there isnt much you can really do to prepare for sulfuric acid and shrapenel of the casing coming toward you. Then assume you manage to be unharmed, that kind of explosion most definitely fries at least a few electronics down the line of the battery, if not many/all, and you now have an engine bay with a covering of sulphuric acid and whatever was next to it just gained a window and the conveniently placed BEC next to the battery is irreparably damaged , needing extensive eleectrical repair, the master cylinder has acid holes, the paint has imperfections, the plastics are all cracked/broken, the engine has a few melted/broken wring runs, some parts of the intake now have leaks from the shock and melted parts, etc.


Be safe, use a ground point separate of the battery needing a boost. Just might save YOU and potentially a car, but Im betting in a scenario the car is damaged, youre damaged.