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 Parasitic battery drain

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Jimosborn

Jimosborn


Posts : 24
Join date : 2018-09-11
Location : San Diego

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PostSubject: Parasitic battery drain   Parasitic battery drain Icon_minitimeTue Apr 12, 2022 3:50 pm

I have a 96 RMW and have been experiencing parasitic battery drain.
I have replaced the battery, Alternator, and positive and negative battery cables.


I fully charge the battery with a battery charger.
remove the ground cable from the terminal
With 30 mins for the pcm to be fully shutdown - not sure if needed but does not hurt
place a multimeter on current/Amps, plug probes in proper locations com and 10A or 20A depending on the multimeter
Connect one probe to the battery cable and one to the terminal on the battery

Any thoughts on what i am doing wrong?
i have tested with 3 multimeters with the probes are in the proper location to measure DC Amps
I did this same procedure in the past on other cars without issue.


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booster




Posts : 608
Join date : 2020-04-21
Location : Andover, Minnesota

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PostSubject: Re: Parasitic battery drain   Parasitic battery drain Icon_minitimeTue Apr 12, 2022 4:42 pm

If you are getting 10-20 amps of current in the off state, you don't have parasitic, you have a hemorrhage.
You must have a stuck relay or some other non shutting off device in the car.
Time to start pulling fuses and relays, one at a time, to find our where the power is going.

silverfox103, Fred Kiehl and Wojtek like this post

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Fred Kiehl

Fred Kiehl


Posts : 7283
Join date : 2009-11-13
Age : 76
Location : Largo, FL 33774

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PostSubject: Re: Parasitic battery drain   Parasitic battery drain Icon_minitimeTue Apr 12, 2022 5:05 pm

Pull the fuses first, until you find the problem circuit, then troubleshoot the offending circuit.
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Rev Bob




Posts : 499
Join date : 2016-05-24

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PostSubject: Re: Parasitic battery drain   Parasitic battery drain Icon_minitimeWed Apr 13, 2022 4:45 am

Sounds like a module with direct connection to B+, like the blower fan or twilight module has failed.

The divide and conquer strategy is appropriate.
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Fred Kiehl

Fred Kiehl


Posts : 7283
Join date : 2009-11-13
Age : 76
Location : Largo, FL 33774

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PostSubject: Re: Parasitic battery drain   Parasitic battery drain Icon_minitimeWed Apr 13, 2022 7:34 am

The blower fan is not a direct connection to B+.

With that amount of current draw, either something should be running or it should get really hot.
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Rev Bob




Posts : 499
Join date : 2016-05-24

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PostSubject: Re: Parasitic battery drain   Parasitic battery drain Icon_minitimeWed Apr 13, 2022 11:36 am

""The blower fan is not a direct connection to B+.""

Fan module?
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Fred Kiehl

Fred Kiehl


Posts : 7283
Join date : 2009-11-13
Age : 76
Location : Largo, FL 33774

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PostSubject: Re: Parasitic battery drain   Parasitic battery drain Icon_minitimeWed Apr 13, 2022 7:07 pm

The module is a direct connect to B+, but is controlled by the HVAC unit. If it is electronic, it will cause the fan to run at high speed if there is a failure. If the fan does not run continuously, that would not be the problem.
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goldwolfnhn




Posts : 328
Join date : 2019-07-11
Location : Stevens Point, Wisconsin

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PostSubject: Re: Parasitic battery drain   Parasitic battery drain Icon_minitimeWed Apr 13, 2022 7:31 pm

could he have meant the radiator fans?

though my brother had a 93 RMW that had a severe drain, he couldn't even drive 5 miles without having to change batteries, all he figured was that the problem was somewhere on the passenger side, but he sold it to someone looking for a demo car rather than trying to dig through the harness to find the issue
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Fred Kiehl

Fred Kiehl


Posts : 7283
Join date : 2009-11-13
Age : 76
Location : Largo, FL 33774

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PostSubject: Re: Parasitic battery drain   Parasitic battery drain Icon_minitimeWed Apr 13, 2022 7:52 pm

Blower fan is synonymous with heater fan.
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Jimosborn

Jimosborn


Posts : 24
Join date : 2018-09-11
Location : San Diego

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PostSubject: Re: Parasitic battery drain   Parasitic battery drain Icon_minitimeThu Apr 14, 2022 5:15 pm

It was a bad headlight switch.

Sprocket likes this post

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Fred Kiehl

Fred Kiehl


Posts : 7283
Join date : 2009-11-13
Age : 76
Location : Largo, FL 33774

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PostSubject: Re: Parasitic battery drain   Parasitic battery drain Icon_minitimeThu Apr 14, 2022 7:46 pm

Glad you found it.
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PostSubject: Re: Parasitic battery drain   Parasitic battery drain Icon_minitime

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