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

[Delain]

Make

Ram

Model

1500

Year

2007

Miles

190000

Engine

5.7L

I've been trying to find the cause of my battery being drained over a few days time.
Watched a few videos on how to do this; I'm not an automotive electrical expert.

This one seems to be very good to follow.
How to find a short in a modern car fast and easy

But, when I connect my multimeter to check the amp draw before beginning to pull fuses, the readout is much higher than suggested in the video AND the mm lead wires become so hot that I'm afraid that the insulation is going to melt.
I checked one or two fuses just to see if the mm would show a drop when pulling fuses, but then have to stop due to the lead wires becoming so hot.

Procedure:
Disconnect battery negative cable.
Multimeter set at 10Amps position and red lead plugged into the 10A connection.
Connect MM leads between negative battery post and the negative batter cable clamp.
Normal readout should show above/over 50mA (0.05). Mine was showing about "4.35" on the readout to start with.
Start pulling fuses one at a time until the meter reading drops back down to normal level or shows a significant drop.

What am I doing wrong and not understanding?
What should be my "normal" amp reading with the connections shown above, without any problematic circuits?

Thanks in advance,
Delain

 

[billr]

Delain, this got held up for approval because of the link to an external site. The combination of a newbie and external link usually means spam...

Let's hope you get some responses tomorrow; I will study it then myself. Time for ice-cream now!

PS: pull all the fuses and see what current is, should be zero. If you do get 0, then put fuses back in one-by-one. If you don't get 0, disconnect all wires to the alternator and see if that drops current to 0.

 

[grcauto]

I've been trying to find the cause of my battery being drained over a few days time.
Watched a few videos on how to do this; I'm not an automotive electrical expert.

This one seems to be very good to follow.
How to find a short in a modern car fast and easy

But, when I connect my multimeter to check the amp draw before beginning to pull fuses, the readout is much higher than suggested in the video AND the mm lead wires become so hot that I'm afraid that the insulation is going to melt.
I checked one or two fuses just to see if the mm would show a drop when pulling fuses, but then have to stop due to the lead wires becoming so hot.

Procedure:
Disconnect battery negative cable.
Multimeter set at 10Amps position and red lead plugged into the 10A connection.
Connect MM leads between negative battery post and the negative batter cable clamp.
Normal readout should show above/over 50mA (0.05). Mine was showing about "4.35" on the readout to start with.
Start pulling fuses one at a time until the meter reading drops back down to normal level or shows a significant drop.

What am I doing wrong and not understanding?
What should be my "normal" amp reading with the connections shown above, without any problematic circuits?

Thanks in advance,
Delain

You we pulling 4.35 Amps. That is why it drains the battery so fast. You need to pull fuses and note when it drops.

 

[Mobile Dan]

"Connect MM leads between negative battery post and the negative batter cable clamp. " After you do this, you may need to attach an additional (thicker) wire between post and clamp, for about 2 minutes. This helps the vehicles modules to "go the sleep" and power requirements go way down. Then detach the additional wire while watching your meter. It should go from 0 amps to "something". Of course, you want windows open, doors closed, key in the house.

 

[Delain]

Thanks for the help here.
So to be clear, I need to pull all the fuses from the fuse box first. Ensure all extraneous electrical users are off/disconnected (hood light, doors closed with windows open to access the interior, etc.).
Connect MM on 10A setup from negative post to battery cable, ready to take amp reading. Also connect a larger wire between post and cable to help the modules go to sleep.
After ten minutes or so, disconnect that larger wire , take an Amp reading (should be close to zero) and begin reinstalling fuses back in one at a time until I see a spike in the Amp reading.
Then that circuit should be where the draw-down is happening.
Will the initial Amp reading begin to gradually increase as I replace fuses?

Let me know if I'm not understanding fully.

Thanks in advance,
Delain

 

[grcauto]

Do not pull any fuses until after the network goes to sleep. Pull fuses until the current drops. That is the leg with a problem. Did you isolate the alternator?

 

[Mobile Dan]

You may need to figure out how to make the vehicle "think the hood and doors are closed, when they are not".

 

[Delain]

Do not pull any fuses until after the network goes to sleep. Pull fuses until the current drops. That is the leg with a problem. Did you isolate the alternator?

To isolate it, disconnect the wires to the alternator? Or is there another way to "isolate"?
So @billr suggests pulling all the fuses to get a zero reading, then reinstall until I detect a spike.
@grcauto you suggest pulling one by one to find the culprit.

One issue that I experienced as I mentioned, is the leads for the MM are getting way too hot to leave the MM connected during the entire pull them out one by one approach, seems like. That's why I'm concerned and hesitant with how to proceed.
I may just try pulling all at one time then reinstalling, though that won't be fun to track where they all go back in.

Sincere thanks.

 

[billr]

I suggest pulling all the fuses so there would be no current, and no meter-lead heating, until you energized the bad circuit. It is the same process as pulling fuses one-by-one, except that meter-lead heating would only be momentary. If you still find that current draw with all fuses out, then that is a valuable clue too, that could be found early in the fuse in/out testing.

I am puzzled why the meter leads are getting hot at only 4.35A. That meter has a 10A range, so I would expect it came with leads suitable for up to 10A. If the leads are even AWG 22, they should not get hot at 4-5A

PS: Isn't the fuse location/value well-shown on the fuse panel or its cover???

 

[grcauto]

That's a lot of work Bill. He's drawing less than 5 amps. The meter is good for 10 and it can handle that all day long. You need to think this through. That kind of draw is usually easy to find because it is most likely something like a motor or alternator something of that sort.
Did he ever isolate the alternator? Might find that is it. Who knows if he don't tell us.

 

[billr]

Agreed, we need more participation from the OP. If the meter leads are getting "hot", as reported, then the draw would seem to be quite a bit more than 4.35A, no matter what the meter seems to read. Do you understand that I suggested doing your fuse-pull test "backwards" to try avoiding the OP's concern about the leads heating? Things just aren't adding up here; but disconnecting the alt is a must, I feel, and pretty easy to try.

 

[nickb2]

Have not been here for awhile, but thought I would drop in, and this thread is cool.

 

[Delain]

Okay, I finally did the parasitic draw test. I was hesitant in doing this because I haven't done much diagnostic testing with a multimeter. Not confident at all with it.
However, I followed most of the advice received here and I believe I'm getting very close to the cause of the draw.

First though, I will tell you I believe a big part of the problem was having a bad battery and that may well have had something to do with the high amp reading and over-heating wires, described above.
I bought a new battery and although it seems there is still some sort of short drawing the charge down, the new battery holds its charge much longer. I spent several weeks tracking the output reading of my old battery to see how the draw was affecting it. Finally, the old batt would not go even a day without needing to be GooLoo-ed (boost-jumped).

So today, I began the testing by connecting the MM leads between negative terminal and negative batt clamp. And as @Mobile Dan suggested, I connected a large size wire between the negative terminal and the disconnected neg-clamp so the truck modules would be able to "go to sleep" before beginning the test. I gave it about fifteen minutes before disconnecting the sleep wire.

No, I did not isolate the alternator simply because I didn't know how. I asked above in a post above but don't see that I got a response on that (may've missed it).

This image shows the green module-sleep wire connected between negative terminal and clamp prior to testing.

I did the "reverse" test method (suggested by @billr) by pulling all of the fuses out at the beginning (after disconnecting sleep-wire).
MM readout was indeed 0.00.
Note - MM set to 10A with red lead plugged in to the adjacent 10A connector.

To keep track of fuse locations, I made up this fuse map adhered to a block of foam. Stabbed each fuse into its appropriate location on the map and then re-inserted in fuse box socket one at a time watching for amp spikes.

Some of the fuse modules didn't have prongs, so I simply wrote on them with their slot number after removing them.

I started at the top of the map with replacing the fuses one at a time. MM remained at 0.00 until I got to . . .
#31 - power train control module - jumped to 0.01
So, I pulled it back out and left it out for remainder of testing.

Then, #22 - ignition switch - jumped to 0.09
Pulled it back out, went on with other fuses.

All went well until I re-inserted the dual fuse assembly at #10/11 - see fuse chart - TRS assembly & powertrain control module (multiple others)
This spiked to >3.00 but then steadily decreased to 0.18. It didn't seem to want to go back to 0.00.
So, I re-attached the sleep wire and readout decreased to 0.01 but then settled at 0.02.

I have no idea what this means.
It seemed that this fuse woke up a bunch of modules, perhaps, that eventually went mostly back to neutral.

I did pull it back out so the MM would go to 0.00.

Continued with remaining fuses.
All were fine except for #5 - sunroof - jumped to 2.81

At the moment, I'm suspecting #5 is my problem circuit. I will work on taking apart the overhead sunroof control cover and see if I can find a wire that has a break or tear in the insulation.
I've replaced all fuses except for #5 and will re-inspect what the MM is showing as so-called final reading. Yesterday it was showing 0.07/0.08 as the final after all fuse back in except #5.

I know this is a an extra long post, but I felt I needed to describe everything I did so the experts here would be able to help.

I would appreciate any information regarding your thoughts on the current spikes with #31, #22, and #10/11 especially.

Thanks in advance,
Delain

 

[billr]

Agreed, #5 is probably the culprit. The others can be explained by the PCM (10&11) needing time to "go to sleep" after the fuses are first installed and the PCM powered; as well as other devices needing memory retained, like radio/clock, seat positions, alarm, remote start, etc.

Since current went to 0 with all fuses out, no need to wonder about the alternator any more. However, most alts have one big wire connected to the back (opposite side from drive pulley) with a nut and stud; also about four smaller wires in a single connector. Simply disconnect the connector and remove the big wire to get the alt out of the circuit. The big wire is "always hot", so be sure to insulate the bare terminal on its end from ground.

 

[Delain]

@billr
Appreciate you reading through the novella.
And excellent information; thanks.

Anyone - What should the normal amp draw MM readout be if there are no problematic circuits?

Thanks in advance,
Delain