Truck won’t shut off!!

[ShadowsPapa]

Given a fully functional alternator, and all things being equal, I didn't think you could stop a running an engine by simply disconnecting the battery.

Glad you mentioned all things being equal.........
I'd need to study some schematics and PCM wiring diagrams but I have wondered if the control for the output of the alternator - in other words, the field (rotor) isn't supplied to the PCM via the battery (likely main battery)
The ASD does get power via the main battery so it's also possible it opens the ASD relay, killing the engine.
And this reminds me - there are run relays involved - wonder if one of those relays is stuck - the points stuck together due to a bit much heat/current. I'd have to do some looking over of those schematics and wiring diagrams as well but a stuck run relay - I wonder......
Again, can't wait for a detailed response as to what was found.

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[whysoserious]

Glad you mentioned all things being equal.........
I'd need to study some schematics and PCM wiring diagrams but I have wondered if the control for the output of the alternator - in other words, the field (rotor) isn't supplied to the PCM via the battery (likely main battery)
The ASD does get power via the main battery so it's also possible it opens the ASD relay, killing the engine.
And this reminds me - there are run relays involved - wonder if one of those relays is stuck - the points stuck together due to a bit much heat/current. I'd have to do some looking over of those schematics and wiring diagrams as well but a stuck run relay - I wonder......
Again, can't wait for a detailed response as to what was found.

Oh, yeah. Hadn't considered the ASD getting power from the main bat. That would/should kill the beast. It appears on the JL in is getting power from the battery...

FUSES_RELAY---ASD---3.6L.pdf (jlwranglerforums.com)

 

[ShadowsPapa]

Oh, yeah. Hadn't considered the ASD getting power from the main bat. That would/should kill the beast. It appears on the JL in is getting power from the battery...

FUSES_RELAY---ASD---3.6L.pdf (jlwranglerforums.com)

Loss of 12v power (from battery) kills the relay, stopping fuel pump, injectors and ignition coil as I recall.
I know it's existed since the early 1990s in EFI engines.
I had totally forgotten how it worked when my Eagle (with 4.0) stopped running on the way to a car show and I couldn't figure out why the fuel pump wasn't running. Then I realized - if the engine isn't running, it only powers the fuel pump for 1 to 2 seconds when the ignition is first powered on for cranking (on a 4.0) and the fuel pump doesn't run again until the engine is running. I finally realized - uh, I have to manually fire the fuel pump relay to get the pump to run to check it and fuel pressure/output due to that. So it was fresh in my mind with this thread.

 

[Sparty97]

With a quick search, it looks like this is the last conversation about this issue.

I've started to have issues getting the truck to shut down. I'll hit the button like normal and hop out and then realize the engine is still running. This has happened 3 times in the last 10 days. On 1 occassion, it took me about 10 minutes of trying everything under the sun of getting it to shut down. Nothing... then all of a sudden 60 seconds later while I was Googling the issue... it just shut down.

The other two times, it took 8-10 attempts before it shut down.

I do have the Stop/Start disabled at startup each time.

I'm comfortable in forcing it to shut down via fuses but I'd rather get it fixed permanently just in case my wife is driving it next time.
Not sure if it is as simple as replacing the button assembly itself or if I have to go farther. https://www.moparfactoryparts.com/oem-parts/mopar-ignition-switch-module-68307356ac?

 

[Hootbro]

I do have the Stop/Start disabled at startup each time.

Do you have a device that is disabling it or are you manually disabling it after start?

 

[88mmm]

This is usually caused by a failing Star connector. Green one behind the glove box.

 

[jeepstertim]

Interesting about not disconnecting the battery. Here in Qatar, the accepted method of changing the battery at the quick-fit places, is to leave the engine running when changing to retain ECU, memory, coding etc. They did it on the Merc ML500 (sooooo many electrical things) I had before the JTR, at the time seemed like a good idea!

 

[Hootbro]

Interesting about not disconnecting the battery. Here in Qatar, the accepted method of changing the battery at the quick-fit places, is to leave the engine running when changing to retain ECU, memory, coding etc. They did it on the Merc ML500 (sooooo many electrical things) I had before the JTR, at the time seemed like a good idea!

That is so risky to damage electronics changing a battery while the vehicle and alternator is running.

That does not surprise me in places like that. Sketch is the name of the game in many parts of the world. While I would not necessarily put Qatar as third world, like many of those rich Middle Eastern countries, they import third world labor and their bad practices.

 

[Sparty97]

Do you have a device that is disabling it or are you manually disabling it after start?

Tazer JL Mini - automatically disables it after startup.

 

[DailyMoparGuy]

So I swapped the switch with a friends and same deal. Dealership says there’s a short on the power side of the circuit that’s not allowing the system to turn off

What was the final culprit of your issue? My truck isn’t turning off either. Well, a delayed turnoff 5-10 minutes after pressing the button.

 

[Lunentucker]

What was the final culprit of your issue? My truck isn’t turning off either. Well, a delayed turnoff 5-10 minutes after pressing the button.

You may want to continue with your new thread.

" Last seen Dec 18, 2023 "

 

[DailyMoparGuy]

You may want to continue with your new thread.

" Last seen Dec 18, 2023 "

Ah shit. Am I gonna end up like him too ?

 

[Smitschke]

What was the final culprit of your issue? My truck isn’t turning off either. Well, a delayed turnoff 5-10 minutes after pressing the button.

Dealership tried to verbally blame my aftermarket stereo. However when the tech brought my jeep out he showed me a faulty accelerator pedal with a burnt pin. When I asked him about the stereo he looked confused. “It’s all in my write up on the work order man, I dunno what the advisor is reading”

 

[DailyMoparGuy]

Dealership tried to verbally blame my aftermarket stereo. However when the tech brought my jeep out he showed me a faulty accelerator pedal with a burnt pin. When I asked him about the stereo he looked confused. “It’s all in my write up on the work order man, I dunno what the advisor is reading”

At least your issue wasn’t silly….a wet U.S. map book under my rear seat shorted the RF hub which I assume is connected to Uconnect. Then I’m also assuming UConnect is connected to the ignition switch one way or another? I don’t know, I’m guessing here.

How the map that I haven’t seen in 2+ years got wet you ask? I don’t know, but my best guess is a leaky rear window.

That’s what I get for throwing unorganized junk under the rear bench for 3 years I guess. So much for tax refund fun this year!

 

[Hootbro]

Then I’m also assuming UConnect is connected to the ignition switch one way or another? I don’t know, I’m guessing here.

RF Hub has like 10 discreet signals in the starting circuit. So it is intertwined pretty well.

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