Parasitic draw

Tiny
EDWARD SCHOOLEY
  • MEMBER
  • 2014 DODGE CHALLENGER
  • V6
  • 2WD
  • AUTOMATIC
  • 55,000 MILES
Hello. I have received some excellent guidance on your website. So, thank you in advance.

Problem: Battery drains after sitting for days. Battery will recharge. However, it will die again after sitting for a week or so.

To diagnose the issue, I used a multimeter and removed a couple of fuses from the rear fuse box. One that was drawing too much current was linked to the AC Heater/Cluster/Security Module. This is where the diagnoses ends. I am not sure if I should be looking at the A/C relay or something else. I know where the relay is, and I am trying to set up my next course of action. I want to have several ideas in mind, before setting myself up for disappointment. Anything you can suggest? Thank you much.

Edward
Monday, September 6th, 2021 AT 3:14 PM

5 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

I'm not sure which fuse is where you found the issue. I know that fuse 14 has power at all times and provides battery voltage to the AC/Heater module. Fuses 48 and 22 in the rear box are only powered when the Run Relay is energized. If it was 48 or 22 and you had power with the engine off, we must have a short to power. If it was fuse 14, there could be a short between the module and the fuse. I noted that the fuses all have a splice location in them. Something could be bad at one of those points.

I attached the wiring schematic below for the A/C system. That is where I located the fuses I mentioned based on what you said. Take a look at it and let me know if I have the correct fuses.

Also, here is a link you may find helpful:

https://www.2carpros.com/articles/how-to-check-wiring

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

I had to cut each of the two pics in half to make them readable for you. I did overlap them. Let me know which fuse you feel is causing the draw.

Take care,

Joe

See pics below.
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Monday, September 6th, 2021 AT 8:42 PM
Tiny
EDWARD SCHOOLEY
  • MEMBER
  • 3 POSTS
Thank you for your quick reply. The fuse from the rear fuse box and diagram points to #14. Which is for the AC / Cluster / Security Module, based upon the diagram. I don't see anything for a #44. Just a #22. Could it be a bad fuse or AC relay that is drawing current when the car is off? I know you mentioned a short to power. However, I want to be prepared in case it isn't the wiring harness, as mentioned. I attached a photo of the fuse I am referring too, that is measuring draw of 1.5, when the car is off.
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Tuesday, September 7th, 2021 AT 6:05 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

You are correct with fuse 14. What to do is go to each of the components you mentioned and disconnect one at a time to see which one drops the voltage draw. The above schematic shows it going directly to the AC / heater module. I did look at the other things and the same fuse powers them as well via the same color wire.

Let me know what you find or if you have other questions.

Take care,

Joe
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Tuesday, September 7th, 2021 AT 6:44 PM
Tiny
EDWARD SCHOOLEY
  • MEMBER
  • 3 POSTS
I have to mention that everything you mentioned is accurate to diagnose the draw, based upon the issue with where the draw was coming from. However, I made a mistake and I forgot to let the vehicle rest before using the multi meter. Since the fuse box is in the rear, and the last thing to draw current was the trunk light, this needs to be shut off and then wait at least 45 minutes before measuring the true draw. I did remove my aftermarket radio, that was initially drawing current from battery. However, the #14 fuse still showed current. Its because I didn't wait long enough before I tested it with the multi meter. Anyways, I learned the hard way. Thank you for your time. Much appreciated.
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Wednesday, September 8th, 2021 AT 2:07 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,755 POSTS
Hi,

That is good that you determined that isn't the issue. As far as the draw, have you located a different area of concern or was it the radio?

Joe
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Wednesday, September 8th, 2021 AT 8:38 PM

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