Parasitic Discharge

Tiny
XRIGHTOFFTHERIPX
  • MEMBER
  • 2022 RAM 1500
  • 5.7L
  • V8
  • 4WD
  • AUTOMATIC
  • 86,000 MILES
My truck has recently developed a parasitic battery drain. The truck runs and drives fine once started, and the alternator seems to be charging (around 13.8–14.0V while running). However, when the truck is shut off, the battery voltage drops steadily and the truck won’t restart after sitting for a short period.

Using a multimeter, I measured a 3.5 amp parasitic draw with the truck shut off, which is way above the normal spec (
Friday, August 29th, 2025 AT 6:49 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yep, 3.5 amps is way above normal. Start by opening the door and closing the latch manually. Then let the truck sit for 45 minutes, then pull fuses one at a time until the draw drops to a normal amount, 20-50 milliamps (0.02-0.05). This will tell us which system is misbehaving. Also, check the obvious stuff like a glove box light, power mirror switch stuck. Also, with the engine cold see if the AC clutch is warm, this will tell you the compressor relay is stuck on. Please go over this guide to help as well.

https://www.2carpros.com/articles/car-battery-dead-overnight

Make sure to open the door latch before you try and close it. Please let us know what happens.
Was this
answer
helpful?
Yes
No
Saturday, August 30th, 2025 AT 9:53 AM

Please login or register to post a reply.

Related Battery Drain Content

How to Test for a Battery Drain-Draw
VIDEO
How to Test for a Battery Drain-Draw
Instructional repair video
Battery Parasitic Drain Repair
GUIDE
Battery Parasitic Drain Repair
A car battery should hold its charge for a few months before needing to be recharged, if not the battery has gone bad or the car has a parasitic draw, something is staying ...