Parasitic Diagnostic Testing on 2007 Ram 1500 5.7L (what to expect for mm readout)

billr

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Roughly speaking, when you first turn off the engine and shut everything else down (radio, heater, lights, etc), I would expect current to be in the 0.5 to 1.5A range. After everything controllable has been off for about 15 minutes, current should drop down to about 50mA
 

grcauto

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Unplug the sunroof motor and check.
Motors like that and things like alternators are by far the biggest culprits to parasitic draw. Next are bad modules.
That would have been one of the first fuses to test. Any circuit that feeds motors.
 

Delain

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After reconnecting battery, leaving the sunroof #5 fuse out for now, idling to let the battery get a bit of a fresh charge, the MM readout was at 12.85.
I believe this is good from what I've read. Reminder - this is a new battery.

Today, took a reading without running the truck, sat overnight; the reading is at 12.39.

What day-to-day drawdown should be considered as acceptable?
I was a disappointed that it had dropped down this much.

I plan to leave the #5 fuse out until I have time to try to track down the short; a wire or the motor. We don't use the sunroof much at all; forget that I even have a sunroof most of the time.

Thank you,
Delain
 

billr

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Normal draw varies,depending on the vehicle and how many gizmos are installed that need to be kept powered. The chart you posted in reply#13 shows a lot of potential parasites. Things like sat, remote start, remote entry, alarm, etc. Are you sure the glove-box and under-hood light are turning off?

Your battery should have a label with amp-hour rating. About 75 A-Hr is typical for an automotive battery, and that would be maximum, probably if a new battery was drawn done slowly to about 10V. If your drain is just 50 mA, there would be a 1.6% discharge per day. Keep in mind that battery voltage vs. state-of-charge is not linear, and is affected by temperature, too. A reading taken when the engine compartment (and battery) are relatively hot will always be higher than when the battery is cold.
 

grcauto

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After reconnecting battery, leaving the sunroof #5 fuse out for now, idling to let the battery get a bit of a fresh charge, the MM readout was at 12.85.
I believe this is good from what I've read. Reminder - this is a new battery.

Today, took a reading without running the truck, sat overnight; the reading is at 12.39.

What day-to-day drawdown should be considered as acceptable?
I was a disappointed that it had dropped down this much.

I plan to leave the #5 fuse out until I have time to try to track down the short; a wire or the motor. We don't use the sunroof much at all; forget that I even have a sunroof most of the time.

Thank you,
Delain
Check for draw again. I wouldn't rely on voltage test of battery.
 

Delain

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Check for draw again. I wouldn't rely on voltage test of battery.
How would you recommend I proceed with that if I've gone through all of the circuits as I outlined?
I sincerely want to figure this out.

Pulled #5 and leaving it out until I have time to disconnect the actual sunroof motor.
Resting(?) draw seems to be showing 0.07 which I assume is 70mA.

@billr - agreed that "The others can be explained by the PCM (10&11) needing time to "go to sleep" after the . . . ", so what do you think I am looking for?

Thanks in advance,
Delain
 

billr

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The first step is exactly what you are doing; leave the sunroof disconnected (#5 fuse out) for enough time to have confidence the problem is in that circuit. A week? Two weeks? Month?

Assuming the sunroof is the culprit, it would be great if we could get a schematic of the circuit posted here. In absence of that, disconnecting the SR motor would get it a "yea or nay" verdict. I doubt it is the motor, though. Motor like that rarely fail shorted, and should not even be powered at all when the SR isn't being moved. I expect the problem to be in wiring or the SR controller/switch.
 

nickb2

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ok,late to game as usual, but I did take time to read a bit.

I would say 70ma is not ideal, but this is an industry considered normal value.

ideal is aprox 50ma, so without over saying what billr said, it all depends on what aftermarket stuff is in this ram.

the industry per sey say 50 to 85ma.

sometimes, the extra 20 to30 ma is often due to your measuring equipment.

sometimes, if you fall on a intermittent draw, most often a can bus waking up for nothing, very hard to pin point without a scope and some form of overnight data logging.

But quite frankly, once you fix the sunroof issue, maybe you go down to 50, cuz if my memory serves right, the antitheft module is always on and checking that circuit,

I know this is not vehicle specific, it for a 2004, but here is a on line free shop manual. But I tookm time to check it, and yes mux line on if circuit not monitored.

page 385, fused accessory relay output, that is your IPM (integrated power module)

hope you like this link, even though it is a 2004, 2007, very similar.

anyway, enjoy



Screenshot (3).png
 
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nickb2

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mux line, and how it works. low key and only used for simple input and output.

If you really want to square it down, pull the fused accessory relay, that cancels all, and you should hopefully see the ideal 50ma.

At this point I am just being confusing, but I was extremely happy to find this whole manual on line for free.


so if the sunroof module is no longer talking to the ipm, mux line on,

so give this a try, pull that relay, post back what you meter is reading once all module go to sleep.

if you go down to50ma, you are golden.
 

billr

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I forgot to mention... digital readouts are never more accurate than /- 1 count in the least-significant digit. That "0.07A" might have been either 60 or 80 mA. In fact, most meters specify accuracy as +/- 2 or 3 counts, check your manual.
 

Delain

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mux line, and how it works. low key and only used for simple input and output.

If you really want to square it down, pull the fused accessory relay, that cancels all, and you should hopefully see the ideal 50ma.

At this point I am just being confusing, but I was extremely happy to find this whole manual on line for free.


so if the sunroof module is no longer talking to the ipm, mux line on,

so give this a try, pull that relay, post back what you meter is reading once all module go to sleep.

if you go down to50ma, you are golden.
Hey @nickb2, thanks for chiming in and giving your thoughts and the manual.

So, which is or where is the "... fused accessory relay ..." ?
Is it #11 on the fuse chart?
And I would pull it and leave it out just for the time of checking the resting draw, correct?

I'll try to test this out later today once I know where the relay it located.

Thanks in advance,
Delain
 

Delain

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So, which is or where is the "... fused accessory relay ..." ?
Is it #11 on the fuse chart?
And I would pull it and leave it out just for the time of checking the resting draw, correct?
 

billr

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English is not the primary language for nickb2, he might have missed that you have already isolated the problem to the sunroof circuit and have pulled fuse #5 to prevent the (excess) parasitic draw. That is still correct, everything is fine as long as fuse #5 is out? (Sunroof inop, of course).
 
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