Ram 2013 dead battery accessory

[zmar5000]

I have a 2013 Ram 1500, crew cab. Whenever I leave ignition switch in accessory mode the battery is drained 10-5 minutes. I tested for power usage in accessory and is drawing 7 amps! I start pulling fuses and my fuse number 57 labeled transmission drops it down to milliamps like it probably should be correct? Can anyone think of a reason it would powering transmission in accessory??

 

[chopperman1]

Even at 7 amps your battery shouldn't die in 10 minutes. I would have the battery load tested, my bet is it's bad.

 

[Jeepwalker]

Maybe you know this but on most modern vehicles, the computer goes through a few stages of 'shutdown' after the vehicle is turned off. The initil amp reading can be deceivingly high at first. You must wait till the computer goes into it's final 'sleep mode' usually ~ 20-30 minutes after the last ignition activity, before you can get an accurate lowest-amp-draw reading. I'm not 100% sure what the exact time is before the Ram computer goes to it's lowest power draw mode. But if you waited 1/2 hour, that should do it. Sorry if you already know this. A lot of guys are unaware and think the first reading is actually a high amp draw if they haven't waited. You might still have a drain, but the computer usually shuts certain circuits down after a while.

This video shows a good (easier) way to hold the multimeter probes on the battery to get a good reading. Better than me trying to explain it.

Car Battery Drains Overnight Or After Days Of No Use! PARASITIC DRAIN

Car battery drains overnight(dies), or after days of no use, parasitic drain, parasitic draw, engine will not start. How to easily find/locate/identify the s...

www.youtube.com

 

[csuder99]

There are two issues here: As already noted, the battery shouldn't die in 10 minutes with a 7A load. Load testing might not necessarily declare it bad as long as the battery delivers enough current from a full charge. If it can't deliver high current after 10 minutes of discharge the battery is at the end of its life. (BTW a test I learned is to have the head lights on for 15 minutes, if the truck still starts the battery is "good enough").
The other issue is the 7 amp draw on the transmission power circuit. There is a relay in the PDC that is controlled by the PCM which in turn sends power the transmission solenoids etc.. I don't think the relay should be active in ACC but I don't know what twisted logic might be applied here. Unfortunately any troubleshooting would require digging into the wiring to see if it is indeed the PCM activating the relay or some damaged/shorted wiring is putting power the relay control side.

 

[zmar5000]

Thanks everyone for the feedback, greatly appreciated! I have had the battery tested several times but I don't think all testers are created equal so I will get a new battery. Thanks for the info on the draw test, I did not know it could stay high for a period of time after ignition is turned on or off. I checked as video instructed at all different times in accessory mode and it always tested 7 amps unfortunately. I think I will need to start troubleshooting the electric starting at the PDC and the relay and start working my way through it. I do not have any reference literature for this vehicle yet to even locate the relay and trace the wiring, any suggestions? Probably see if relay is being energized first after I locate relay? I've also read that the PDC's tend to have a lot of issues on the Rams?

 

[GTyankee]

Wiring diagrams can be found in the Ram Body Builders Guide

Ram Commercial Body Builder Guide - Upfit Your Truck

Ram Trucks Body Builder's Guide has information you need to upfit your truck. Explore the Body Builder Guide for dimensions, electrical & technical guides.

www.ramtrucks.com

 

[zmar5000]

Ram website shows being out of stock on wiring diagram for my truck, everyone is out of everything nowadays I guess. Where else do you think I can find a really good, accurate wiring diagram for this truck?

 

[DILLIGAF]

Where else do you think I can find a really good, accurate wiring diagram for this truck?

all the service manuals are here https://www.ramforum.com/threads/pdf-service-manual.32145/