2020 Ram 1500 Will Not Reliably Start

[nichobt]

So, the Amperage goes down over time after it is connected. Do I let it sit 10 minutes once I connect the multimeter or just after I remove the negative battery cable?

 

[Richard320]

Let me know if that is the correct setting. If I am right, it is a 1.5A draw at rest

Looks like. But make sure the key fob is well out of range so everything goes to sleep.

Connect the ammeter then wait ten minutes or more to take a reading. If you disconnect the battery and then connect the ammeter, you're essentially reconnecting the battery and everything will wake up again.

 

[nichobt]

Aaaand, I blew the fuse on the multimeter when I opened the door to check the other fuse box. How do I access the other fuse box if it draws more than 10A when I open the door to he truck? Do I need a multimeter with a higher amp rating?

 

[Richard320]

Aaaand, I blew the fuse on the multimeter when I opened the door to check the other fuse box. How do I access the other fuse box if it draws more than 10A when I open the door to he truck? Do I need a multimeter with a higher amp rating?

No. You need to not disturb anything while you're waiting for everything to go to sleep.

 

[HSKR R/T]

Aaaand, I blew the fuse on the multimeter when I opened the door to check the other fuse box. How do I access the other fuse box if it draws more than 10A when I open the door to he truck? Do I need a multimeter with a higher amp rating?

Keep the door open

 

[nichobt]

Keep the door open

Ok, well I have to go buy some fuses and will report later. So, the problem I have is that if I open the door at all with the multimeter connected then the lights etc will all turn on inside the truck, even with the key 100+ft away. As soon as it connects the battery to the negative cable it ends up turning it all on. I am not sure how I do this without those lights, etc turning on?

 

[nichobt]

Ahh, I see it now. You have to disable the door switch to do it or have a different person inside....oops

 

[nichobt]

Ok, so I think I narrowed it down to F43 Fuse inside the cabin. That is coming up as Port Diagnostics, Mod CD, and Front and Rear USB. Not really sure where to start with that...

 

[HSKR R/T]

Ok, so I think I narrowed it down to F43 Fuse inside the cabin. That is coming up as Port Diagnostics, Mod CD, and Front and Rear USB. Not really sure where to start with that...

USB hub issue? Do you have anything plugged into USB ports?

 

[nichobt]

USB hub issue? Do you have anything plugged into USB ports?

Nothing at all in the rear USB ports. Rarely ever do. I suppose it is possible that my son used it at some point, but there is not anything currently in there. I'm not sure I've ever used the diagnostic port, though.

 

[dski]

Just circling back I’ve never done this on my ram but most vehicles you’ll need to wait 20+ min for everything to go to sleep. Like other said don’t disturb doors, stay away from the key fob etc.


Probably should be like under 50 miliamps

I have a clamp amp meter which is nice you don’t have to unhook anything and it handles more amps

 

[nichobt]

Just circling back I’ve never done this on my ram but most vehicles you’ll need to wait 20+ min for everything to go to sleep. Like other said don’t disturb doors, stay away from the key fob etc.


Probably should be like under 50 miliamps

I have a clamp amp meter which is nice you don’t have to unhook anything and it handles more amps

Yeah, I experienced the same. I hooked everything up and went inside for a good 30-45 minutes. The multimeter settled at about 145ma by then. When I removed the F43 Fuse in the cabin is when it dropped to about 20-4ma. I couldn't figure out how to disable the door ajar sensor so I just crawled through the open window. Not convenient, but it worked.

I do suppose I could see if removing the fuse would cause any problems or errors. I don't really need the rear USB, but not sure about the diagnostics port or CD Mod(CD?).

 

[Darksteel165]

Yeah, I experienced the same. I hooked everything up and went inside for a good 30-45 minutes. The multimeter settled at about 145ma by then. When I removed the F43 Fuse in the cabin is when it dropped to about 20-4ma. I couldn't figure out how to disable the door ajar sensor so I just crawled through the open window. Not convenient, but it worked.

I do suppose I could see if removing the fuse would cause any problems or errors. I don't really need the rear USB, but not sure about the diagnostics port or CD Mod(CD?).

I don't know how it affects draw, but those devices stay running for a long time I forget how long. There are LEDs in the front USB ports too.

 

[nichobt]

Well, I might just remove the fuse and see if everything else works. Or I could start with disconnecting the USB hub in the back seat and see if that changes anything.

 

[Darksteel165]

I would just yank the fuse. Make sure it fixes the problem then go from there.

 

[nichobt]

So, I didn't remove the fuse, but somehow my truck has started without a jump the last two days. Is it possible a fuse was loose and shorting or causing the truck to use excessive power while off? Seems unlikely, but it has worked for two days straight.

 

[Darksteel165]

So, I didn't remove the fuse, but somehow my truck has started without a jump the last two days. Is it possible a fuse was loose and shorting or causing the truck to use excessive power while off? Seems unlikely, but it has worked for two days straight.

You didn't remove the fuse and keep it out, or you didn't remove it at all?

I wonder if you removed the fuse and put it back in and it rebooted the electronics that were being powered acting funky.

 

[nichobt]

You didn't remove the fuse and keep it out, or you didn't remove it at all?

I wonder if you removed the fuse and put it back in and it rebooted the electronics that were being powered acting funky.

Yes, I did remove a bunch of fuses and put them back in. That is what told me it was F43. But, maybe it did reboot something? It could be that it was not shutting down one system completely even after 30-60 minutes of the truck being off and now it is. I am going to hope this is the end of this saga! The only sad thing is I replaced the starter to do this. AutoZone won't take it back now, but that is fine. I'll keep the old starter core just in case I need it at some point.

Thanks for the help everyone!

 

[RHCan]

You are correct—-1.5 amps

 

[dski]

Spectating these forums feels like there's a lot of minor electrical gremlins that like a module reset/reboot. Maybe that happened here.