Parasitic Drain on 30A Fuel ECU Circuit

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May 11, 2021
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San Jose, CA
Recent new battery and it drained out after not driving it for 4 days. Tracked down the draw to 30A Fuel
ECU Circuit. Any ideas on how to check the circuit. I was thinking of starting with the ignition switch. Thoughts?
 

Gilaguy23

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Apr 12, 2021
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Q town New Mexico
Without looking at a manaual Im not sure which is the fuel pump relay so I cant speak to that at the moment. But after charging the battery or after a good drive where it will come up to 14.3ish volts it would normally settle down to 12.6 volts. Occasionally checking with a digital volt meter after sitting for a couple days It shouldent drop below that by much if things are normal. if you pull that relay your battery voltage should maintain the 12.6ish volts. I suppose another quicker way would be to get the battery charged,turn off everything,engine,key,ect,ect and pull each relay under the cover one at a time. If one is hung up you will feel/hear it click as the contacts open. Relays do get stuck sometimes,just ask a durango or Chysler mini van owner. Unforunatly in their case the entire fuse box needs to be removed and a new relay soldered in or the entrire fust panel replaced. Another brilliant engineering feat from DC.
 
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Stoopid Jeep

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Dec 25, 2021
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North Idaho
This little tool from Harbor Freight is useful for finding amp draws:
amp.jpg
 
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San Jose, CA
I was able to find the circuit diagram for the fuel pump relay in my Haynes manual, but I can’t seem to find the diagram for the auto shutdown relay, which is also on this fuse to test the wiring. Anyone have the diagram for the circuit that includes the auto shutdown relay? Is the auto shutdown relay also called “b+ latch relay”…see picture.

67355DFF-FC03-4605-8032-36D33756CB7A.jpeg
 
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