Engine/Transmission (1998.5 - 2002) Me too battery drain/short situation

[jandtjil]

Having been waiting for some warmer wx (okay just procrastinating) to dig into a battery drain situation. Began with slow or no turn over condition when it had sat for a day or two, battery condition now is overnight and it displays the condition. However, if I plug the block heater in for an hour or so and bring the block temp up, it often times will turn over and start.

I have checked most of the grounds (did not check the bundle beneath the battery)
have ran a meter in line and show about 1.48 amp draw (yikes) pulled every fuse (under-hood and door jamb) no drop
not exactly true I did not pull the Alt 145 amp fuse
Alt is a few months old 6-8 months
Thinking maybe it was the heater grid initially I pinned the relay control wires (yellow/orange) from the ECM and had about 44mv present with key off (should be 0 from my reading)
No codes using OBD scan tool
Questions...
A Can an ECM be bad and not show codes?
B Can bad diodes/regulator in alt cause above crazy voltage conditions?
C Sensor problem?

Not above taking it in for a diagnostic just prefer not to

JJ

 

[jandtjil]

update
Had alternator checked and it was bad (rebuilt Bosch only 8 months old), am awaiting replacement.
JJ

 

[Bob Wagner]

Congratulations on finding the cause. It was nice to talk to you.

 

[jandtjil]

Thanks Bob, the pleasure was mine.
Unfortunately, the alternator is not the only culprit. After remounting the alt I am still loosing amps, will re-check pulling fuses and start investigating individual battery leads...?

At this point the batteries are totally fried, they will hold a charge overnight (unhooked) showing 12.4 to about 12.6v but their cranking power is zero.

 

[seafish]

Did you find the draw yet?? …many times it is through the IOD (ignition off drain) fuse…I THINK that it is the #12 rot maybe #17 position in your 2nd gen trucks fuse box…something like the glove box light is sticking on.

Also How old are the batteries??

 

[jandtjil]

No haven't found it yet.
I will check all the fuses again have worked through them once before and didnt see the drain drop off on the meter
The batteries are 2008 models but have endured a couple "Oh crap I left the lights on" moments. plus this.. so they are toast. A
Am hoping to find the cause before installing new batteries, but as Bob W and others have mentioned bad batteries give PCM/ECMs fits and can be erratic I guess..
At this point, I certainly don't know.

 

[seafish]

They are correct, low voltage/bad batteries can and will cause all sorts of problems/gremlins with your trucks ecm and sensors.

Put the new ones, but then also check for draw again overnight after they are installed. If there IS a dra still, you obviously need to find it.

I can't found it right now, but Sag2, a member here who is also a professional mechanic with these trucks, has written up a post that details the best way to find such a draw on these trucks.

There is also this youtube vid which is pretty good--

https://www.youtube.com/watch?v=zdIKNnwEjIs

ANd this step by step wiki which is simple and good--

http://www.wikihow.com/Find-a-Parasitic-Battery-Drain

 

[AllianceDiesel]

I had a battery in my 01 go bad where if the truck sat for more than a day it would draw down the other battery. Replaced both batteries and it can sit for weeks now and start right up

 

[jandtjil]

Yes, being able to let the truck sit without worry about it starting. Those are good times indeed!
Seafish as a matter of fact a few days ago when I began troubleshooting, I watched the exact video! The guy (Eric) has some decent videos posted..

I guess rechecking the amp draw for a 3rd time was the charm for me, as I noticed that I needed to separate the lead (drivers side battery) to the underhood power center. Removing that, my amp draw dropped about .03 amps (IOD), leaving the starter as the culprit. ??
Disconnected the relay wire and the amp draw remained unchanged...Will pull the starter and see whats going on.

 

[jandtjil]

Wire from relay into solenoid is missing.

 

[jandtjil]

Update
Replaced starter
Retested battery cable to starter with lead to the PDC removed showed no amp drain. Hurray!
Connecting the lead to the PDC shows the amp draw again (about 1.79 amp). Sigh......
Pulled all PDC fuses and relays NO effect.
Pulled all fuses in drivers door, No effect.
Removed trigger wire at starter and tested through PDC, No effect.
Removed engine in line connector from PDC and checked PDC, No effect
Before I go poking around below the PDC, wouldn't removing the fuses/relays have identified a problem up and down stream of the PDC ?
Am thinking maybe when the starter fried the trigger wire leading to the solenoid coil, it could have a also damaged a contact in the PDC / ignition switch ?
Are there circuits leading into the PDC that aren't traceable via a fuse or relay?
JJ

 

[Sticks]

What aftermarket items do you have in your truck? Extended power ports, Radio, Amp, inverter....

Disconnect any and all items that are not OEM with the truck - regardless of who installed them - including alarm system if there is one. Trailer connection(s). May have to start disconnecting wire harness junctions down stream of the PDC.

When you are doing this, are any of the doors open - hood light included (disconnect the pigtail for it). Cab doors open will try to turn on the dome light. Key in the ignition?

 

[jandtjil]

Disconnected the Edge EZ yesterday (after reading your advice on another thread) Unfortunately No effect
CD changer are CB are on ignition hot circuits, but I will similarly take them offline.
Will check trlr harness (stock)
Will check splice to back up cam/off of trlr plug power

I have used a quick clamp to secure the door switch and have disconnected the underhood lamp, key has not been in the ignition.
May not get to this today, honey do list awaits but will, and will reply.
Thanks Sticks

 

[jandtjil]

Testing done with
-Pass side battery +pos cable removed (and isolated), and ground cable installed.
-Driver side battery +pos cable removed (also heater grid power and Pass +pos crossover link) and isolated, with ground cable installed on post.
Meter between Driver side +pos post and +pos battery connection point at PDC. Alternator charge cable removed from PDC (and isolated)/ so is the 150A fuse
Doors closed. No key in ignition

CB power disconnected - no effect
CD changer disconnected - no effect
Checked back-up camera splice and while I did not remove it, I noted that it is on a running lamp (license plate light) circuit. Shouldn't this have been covered with 15a PDC fuse?
Before breaking open the factory splices for the trailer connector, I just wanted to ask if the trailer relay in the PDC would cover this?

Would it be a benefit to just go ahead and remove all fuses and relays and leave them out at this point?
JJ

 

[Sticks]

No. You have already done that by pulling one at a time, I presume the same with all the relays.

Now we are looking for something that is drawing power that is not supplied by the PDC or the in cab fuse panel. The ECM and PCM both have constant power draws - disconnect them (one plug at a time).

Trailer plug (7 way RV) may or may not have a constant power feed to one of the 7 posts. Either center, or upper blades (I can not remember which one). Brake controller if you have one may also have constant power.

Now a light draw that would normally be less than one amp, will go up if there is a bad ground connection - hence making sure that all the grounds are clean and tight. Voltage drop tests on those.

 

[jandtjil]

You were correct constant power through PDC fuse#8 appears to run all the way to the connector (pg 8W-54-2)
to tab#4 at 1oclock position
Supplied power to PDC then checked tab#4 for power = Yes,
Pulled Fuse#8 = No power to tab
Checked amp draw = No effect

Disconnect Brake controller - no effect
Disconnect PCM Inside connector - no effect
middle connector - no effect
outer connector - no effect
Disconnect ECM - no effect
Re-assuring the truck that the phone call to different dealerships was nothing, and that I had no intention of trading it off - no effect
will start re-checking grounds

 

[Sticks]

As messed up as this is going to sound...are your batteries clean - no dirt, sweat, etc. on the tops in particular?

I've seen it bad enough once, batteries draining themselves due to the battery acid accumulation and corrosion on the top. You could read a full 12 volts from one post to the plastic top of the battery with a volt meter.

I have also seen issues with the main cable to the starter, and the signal line that run inside the harness with the main.

To confirm, you have pulled relays as well during all of this right?

Missing something simple - we have to be.

 

[jandtjil]

The battery tops are not pristine for sure, I can clean them up.
That makes sense it is a salt of sorts that is forming on top.

Defintely.. I have had the fuses and relays out. No problem clarifying that, and I do appreciate you taking your time on this!
Since I am pretty good at it now, maybe I'll triple check that tomorrow. I was almost disappointed when the drain didn't go away when testing the PCM and ECM.

There may certainly be issues with the starter relay wire running from the relay and with the starter - battery cable. But the testing today was as posted earlier and shouldn't be an issue in the amp drain.
Pass -neg cable attached / Pass +pos cable unattached . Drive -neg cable attached/Driv +pos cable unattached,grid htr battery connection and +pos crossover cable unattached
Basically making a connection between the pos post and battery tab of the PDC with the multimeter to measure the drain.
After posting earlier today I pulled the connector (right by the ebrake) under the dash, similarly no effect.
So I sat down and started looking at the PDC joint connections (#1 & #2) in the manual will make note of color location and polarity maybe prepare to start in there ??? also started eyeballing the circuit from the ignition switch to relay ??
As you mentioned earlier the volt drop test may have to begin arghhhh

For a shop with a DRB tool, would this be an easy kill, or still a mystery with a laptop attached?

 

[Sticks]

You've got something odd going on. An auto electric pro might be able to find this, but I doubt that a DRB is going to nail it down.

With all the PDC fuses and relays, and cab fuses out you were still showing a draw.

Clean the batteries, take the passenger battery out of the loop (chassis ground and crossover only) and verify you still have a drop.

Time to start disconnecting wire harness junctions. I was surprised that you saw no change when you disconnected the ECM and PCM.

What are you using to measure the amperage draw, and how.

 

[jandtjil]

Cleaned battery tops and posts again, then went about rechecking the fuses and relays.
Previously I had removed a relay or fuse one at a time, then replaced it.
Yesterday I removed everything (in PDC and Junc Block) and went about checking each circuit individually, but did not replace them as I kept testing.
The Battery fuse (#1), Engine fuse (#3), Hazard fuse (#4), and the ABS fuse (#11)) all showed draw. Began following each of these circuits to eliminate the condition.
The Battery fuse traced back to 6 circuits in the JB, and while pulling and replacing them; I noticed that the amp draw was jumping even higher.
So I might need to replace the Junc Block. But am not set on that, still spending a lot of time at this point looking for common points in the circuits using the service manual. I have had the dash partially apart, but have never rolled it forward, will need to do some serious reading before I jump into that. But, at least I have a direction to work with this result.
JJ