Parasitic Draw

[FMFHMMWV]

So my battery towards the front of the vehicle went bad. I replaced it with an optima red top. and in 4 days, that went bad too. The battery towards the rear is ok.

Observation 1: I noticed that while connecting the batteries with the key out of the ignition and ignition in off position, it was sparking at the terminal.
Observation 2. This led me to believe that there was a parasitic draw. I disconnected the ground from the starter and found that when reconnecting the batteries, it was no longer sparking at the battery terminals.

Question 1: Does this mean that the starting is bad?
Question 2: How do I know that it is not the starter relay?
Question 3: Any recommendations on starters/relays that I can use to make this truck more reliable?
Question 4: any recommendations on who can rebuild the old starter?

 

[Mogman]

When you disconnected the ground from the starter it was just like disconnecting the batteries, you disconnected everything.
You bought an old left for dead truck now you are going to have to do some troubleshooting, the starter would not be where I would start.
You need to put an ammeter from the battery post and terminal and then start disconnecting things, the trans would be high on the list as would be the EESS box.
BTW you should always replace the batteries in pairs or you will continue to have battery issues.
Now did the battery go dead in 4 days or did the battery go bad??
Is the trans light lit when run switch is off?
Is the three lever light switch in the correct position?

 

[Coug]

This to me sounds like there is some sort of wiring issue, as there is no way that just the forward battery should go dead if the starter is an issue.

Either something is wired incorrectly, or maybe you have a failed 12V relay or diode or something else related to the TCM that is allowing power flow in reverse through a circuit somewhere causing the forward battery to drain, while the rear battery is fine.

 

[Mogman]

Post a picture of the batteries.

 

[FMFHMMWV]

- After I replaced the battery the first time, the truck was shifting fine. when I replace the battery, the truck would start just fine:

Light comes on then off. then it starts but there is a hesitation. Everything functions just fine. truck runs strong and shifts through the gears.

Ill have to find the voltmeter somewhere in the garage to test it.

I have a brand new optima red top. I will purchase a second one to ensure that I am replacing both batteries at the same time.

The new battery went dead in 2 days and when tested at the autozone, they said it was bad.
- Is the trans light lit when run switch is off? I haven't looked. Im worried that when I connect the new batteries, Ill fry something. Do you think I should just connect the new batteries and start testing? How do I isolate the starter?

I think the starter is the culprit because:

1. The hesitation of the start.
2. when I disconnect the ground from the starter to the passenger side head of engine block, The spark stopped happening. there should still be power to everything else right?

-Is the three lever light switch in the correct position? yes sir.

 

[FMFHMMWV]

This to me sounds like there is some sort of wiring issue, as there is no way that just the forward battery should go dead if the starter is an issue.

Either something is wired incorrectly, or maybe you have a failed 12V relay or diode or something else related to the TCM that is allowing power flow in reverse through a circuit somewhere causing the forward battery to drain, while the rear battery is fine.

1. I checked the wiring from under the passenger seat to each appliance and they appear to be in good conduction.
2. I cleaned the negative terminals where they attach to the shunt. all of them are clean and have good wires.
3. The truck does not have have ancillary circuits to cause a draw (car audio, light bar, flir cam etc)

 

[Mogman]

Again when you disconnected the ground wire it disconnected everything, that the terminal no longer sparks means nothing.
Do not do as many do and spend thousands of dollars just replacing stuff, actually find the problem, it could be the starter but also it may not.
Do the work and find the problem.

 

[Mogman]

Also AGAIN post some pictures of your batteries to show how they are wired, something is really wrong if you are killing one battery and the other remains fine

 

[springer1981]

What model truck? Does it have a functional dual voltage alternator? If it's a 3spd and no center tap to the batteries, how would only 1 die? They are wired in series, are they different amperage batteries? You should use a current meter in line and strategically disconnect stuff starting with cb1 and cb2 and see if it effects current draw.

 

[Guyfang]

I highly daubt the Optima battery is "dead". I know they aint what they used to be, but just because someone tells you its dead? No. You need to check it out for yourself. Get a battery charger that is made to charge that type battery. Then load test it. Its very hard to really kill an optima.

 

[FMFHMMWV]

What model truck? Does it have a functional dual voltage alternator? If it's a 3spd and no center tap to the batteries, how would only 1 die? They are wired in series, are they different amperage batteries? You should use a current meter in line and strategically disconnect stuff starting with cb1 and cb2 and see if it effects current draw.

1. it is an M1123.
2. This is a 4 spd.
3. I apologize for being ignorant, but what is cb1 and cb2?

very respectfully,

 

[FMFHMMWV]

A: is the cable that goes to the hot post on the voltage regulator. this is typically attached tothe positive terminal on the rear mounted battery.
B: is the negative which also has the ground for an alpine sound device.
C: This is the shunt that was cleaned and detailed.

 

[Mogman]

OK so it is the REAR battery that is going dead yes?, I thought you said it was the front battery.
What is that cable with the corrugated plastic loom that is connected to the positive terminal of the rear battery connected to.
The picture does not show all the detail you talk about, we cannot see A or C, I am assuming the terminal with the blue on it is going to the 14V tap on the regulator.
Also what is this nasty brown wire going to? (top arrow)

 

[Guyfang]

CB is a Circuit Breaker. I would tell you what it is and where, but I am not a truck guy. Someone will jump in here I am sure.

 

[Mogman]

It looks like your problem is with one of the connections between the two batteries and not any of the 24V items like the starter etc.

 

[Guyfang]

Often, it helps to simply disconnect ALL the cables on the batteries. Then hook them back up IAW the schematic. If someone else before you, or you, have hooked up something wrong, thats the only way you are going to find it.

 

[FMFHMMWV]

OK so it is the REAR battery that is going dead yes?, I thought you said it was the front battery.
What is that cable with the corrugated plastic loom that is connected to the positive terminal of the rear battery connected to.
The picture does not show all the detail you talk about, we cannot see A or C, I am assuming the terminal with the blue on it is going to the 14V tap on the regulator.
Also what is this nasty brown wire going to? (top arrow)

It is the front battery. This time I switched it around to see if the same issue would effect the "good" battery.

A: is the cable that goes to the hot post on the voltage regulator. this is typically attached tothe positive terminal on the rear mounted battery.
B: is the negative which also has the ground for an alpine sound device.
C: This is the shunt that was cleaned and detailed.

The issue is effecting the front battery.

Bottom arrow is positive towards the sound amps. The top arrow I don't know. The wire free floating with the blue shrink wrap is from the voltage regulator. I ended up reconnecting it.

 

[Mogman]

So you swapped the batteries? I am just trying to get a handle on why only one battery is having a problem, if it was a starter or any other 24V load it would drain both batteries, I would start by disconnecting everything connected to the pos of the rear battery, of course make sure that wire from the reg does not get grounded.
Do you have a 4 speed or 3 speed truck?
Also how many amps does the audio system pull, looks like a serious size cable.

 

[FMFHMMWV]

So you swapped the batteries? I am just trying to get a handle on why only one battery is having a problem, if it was a starter or any other 24V load it would drain both batteries, I would start by disconnecting everything connected to the pos of the rear battery, of course make sure that wire from the reg does not get grounded.
Do you have a 4 speed or 3 speed truck?
Also how many amps does the audio system pull, looks like a serious size cable.

It is a 4spd. The audio has been switched off.

 

[Mogman]

Switched off is not the same as disconnected, you need to disconnect EVERYTHING from the batteries and then start carefully re-connecting things until you find the problem.
You have to be careful with a dual voltage system, remove the ground cable from the rear battery and then try ether intentionally or through some failure to pull current from the 24V terminal and you reverse bias anything connected to the 12V tap (this BTW would only pull current from the front battery) as long as the ground cable is disconnected