1

I have a parasitic draw of 280 milliamps with everything turned off and my key fob 15 feet away from the vehicle. I latched the hood latch just in case there is a sensor in it.

I pulled all fuses with no change until I reached the IOD fuse. Pulling that fuse terminated the draw. I don't know where to go from here because I don't know what systems are powered by that fuse and how to determine which system is at fault.

After having my 6-month-old battery tested and recharged, I monitored the voltage drop over several days. It is losing 1/4 volt per day.

Does anyone have a recommendation?

Brian.

Improve this question

2 Answers 2

Reset to default
0

Disconnect the wire harness from the alternator/generator, wait 20 minutes, then repeat the amperage check with your multimeter. If milliamps drop, replace the alternator. The internal diodes of the alternator are part of the IOD but are not on any fuse.

Improve this answer
5
  • isn't fire connection from alternator coming from starter key?
    – Cubic273.15
    Dec 31, 2020 at 6:29
  • Disconnect all wiring or just the main positive feed from the battery?
    – Brian LeCrone
    Jan 4, 2021 at 4:57
  • @Brian LeCrone - Disconnect both battery leads, then disconnect the alternator. Wait 20 minutes, then check the amperage across the battery leads. If parasitic draw disappears, replace the alternator.
    – Carguy
    Jan 5, 2021 at 4:20
  • Check amperage directly across leads while not connected to battery or reconnect positive to battery and check between negative battery terminal and negative lead?
    – Brian LeCrone
    Jan 6, 2021 at 16:30
  • Yes, reconnect the positive lead after you have disconnected the alternator. Check amperage between negative battery terminal and negative lead. If the parasitic draw is gone, the alternator is defective. You are basically removing the alternator from the system in order to isolate it. Also, have the battery checked at an auto parts store. Cheap-o batteries have been known to fail after just a few months.
    – Carguy
    Jan 7, 2021 at 10:52
0

Please always mention the year, make, model, engine size, and transmission type of your vehicle. Based on the information you have provided, I will provide the following answer that applies to many Chrysler, Ram, and Mitsubishi vehicles.

The Ignition Off Draw (IOD) circuit monitors normal draw from the vehicles' electrical components when the ignition is in the off position. The IOD fuse feeds the memory and sleep mode functions for some of the electronic modules in the vehicle and various other accessories that require constant battery current when the ignition switch is in the off position. This includes components like the clock.

The normal draw for most vehicles is 0.005 to 0.035 amperes. Up to thirty-five milliamperes are needed to enable the memory functions for the Powertrain Control Module (PCM) and other modules, which may vary with the vehicle equipment.

Excessive Ignition Off Draw can be caused by:

  1. Electrical items left on.
  2. Faulty or improperly adjusted switches.
  3. Faulty or shorted electronic modules and components.
  4. Intermittent shorts in the wiring.
  5. Aftermarket radio or alarm.
  6. Totally Integrated Power Module.

You need to keep the IOD fuse installed while isolating the circuit causing the parasitic draw. Before attempting to diagnose the issue, make sure your battery is fully charged, all components are turned off, doors are closed, windows up, and wait at least 30 minutes for all systems to time out. Do not touch the steering wheel. Do not lean on the car and make it roll. Do not sit in the car. All of these actions could interfere with your diagnostic results.

I would start diagnosing each circuit that draws from the IOD circuit using an amp clamp. I would also run the car for a while and see if any DTC codes are present.

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .